diff --git a/leetcode/.gitignore b/leetcode/.gitignore
new file mode 100644
index 00000000..70375054
--- /dev/null
+++ b/leetcode/.gitignore
@@ -0,0 +1,3 @@
+/target
+/cmake-build-debug
+/cmake-build-release
diff --git a/leetcode/CMakeLists.txt b/leetcode/CMakeLists.txt
new file mode 100644
index 00000000..d39d33b5
--- /dev/null
+++ b/leetcode/CMakeLists.txt
@@ -0,0 +1,5 @@
+
+cmake_minimum_required(VERSION 3.10)
+project(leetcode)
+
+add_subdirectory(cpp)
diff --git a/leetcode/Cargo.lock b/leetcode/Cargo.lock
new file mode 100644
index 00000000..17184853
--- /dev/null
+++ b/leetcode/Cargo.lock
@@ -0,0 +1,127 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "lc-0001-two-sum"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0002-add-two-numbers"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0003-longest-substring-without-repeating-characters"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0004-median-of-two-sorted-arrays"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0011-container-with-most-water"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0015-3sum"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0016-3sum-closest"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0018-4sum"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0026-remove-duplicates-from-sorted-array"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0027-remove-element"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0034-find-first-and-last-position-of-element-in-sorted-array"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0035-search-insert-position"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0036-valid-sudoku"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0053-maximum-subarray"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0066-plus-one"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0078-subsets"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0083-remove-duplicates-from-sorted-list"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0088-merge-sorted-array"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0128-longest-consecutive-sequence"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0136-single-number"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0137-single-number-ii"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0191-number-of-1-bits"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0217-contains-duplicate"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0219-contains-duplicate-ii"
+version = "0.1.0"
+
+[[package]]
+name = "lc-0220-contains-duplicate-iii"
+version = "0.1.0"
+
+[[package]]
+name = "lc-1114-print-in-order"
+version = "0.1.0"
+
+[[package]]
+name = "lc-1115-print-foobar-alternately"
+version = "0.1.0"
+
+[[package]]
+name = "lc-1116-print-zero-even-odd"
+version = "0.1.0"
+
+[[package]]
+name = "lc-1117-building-h2o"
+version = "0.1.0"
+
+[[package]]
+name = "lc-1195-fizz-buzz-multithreaded"
+version = "0.1.0"
+
+[[package]]
+name = "lc-704-binary-search"
+version = "0.1.0"
diff --git a/leetcode/Cargo.toml b/leetcode/Cargo.toml
new file mode 100644
index 00000000..79c66a42
--- /dev/null
+++ b/leetcode/Cargo.toml
@@ -0,0 +1,11 @@
+[workspace]
+resolver = "2"
+
+members = [
+ "rust/*.*"
+]
+
+exclude = [
+ "cpp",
+ "problems",
+]
diff --git a/leetcode/LICENSE b/leetcode/LICENSE
new file mode 100644
index 00000000..d41c0bd9
--- /dev/null
+++ b/leetcode/LICENSE
@@ -0,0 +1,232 @@
+GNU GENERAL PUBLIC LICENSE
+Version 3, 29 June 2007
+
+Copyright © 2007 Free Software Foundation, Inc.
+
+Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
+
+Preamble
+
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+
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+
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+
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+The precise terms and conditions for copying, distribution and modification follow.
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+
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+
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+
+15. Disclaimer of Warranty.
+THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+16. Limitation of Liability.
+IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+
+17. Interpretation of Sections 15 and 16.
+If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.
+
+END OF TERMS AND CONDITIONS
+
+How to Apply These Terms to Your New Programs
+
+If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
+
+To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.
+
+
+ Copyright (C)
+
+ This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with this program. If not, see .
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:
+
+ Copyright (C)
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.
+
+You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see .
+
+The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read .
diff --git a/leetcode/README.md b/leetcode/README.md
new file mode 100644
index 00000000..1a85c5eb
--- /dev/null
+++ b/leetcode/README.md
@@ -0,0 +1,5 @@
+
+# About
+
+Leetcode problems and solutions
+
diff --git a/leetcode/cpp/0002.add-two-numbers/CMakeLists.txt b/leetcode/cpp/0002.add-two-numbers/CMakeLists.txt
new file mode 100644
index 00000000..1bd738b2
--- /dev/null
+++ b/leetcode/cpp/0002.add-two-numbers/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0002-add-two-numbers
+ main.c
+ )
diff --git a/leetcode/cpp/0002.add-two-numbers/main.c b/leetcode/cpp/0002.add-two-numbers/main.c
new file mode 100644
index 00000000..899bd9dd
--- /dev/null
+++ b/leetcode/cpp/0002.add-two-numbers/main.c
@@ -0,0 +1,69 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* new_node = malloc(sizeof(struct ListNode));
+ assert(new_node != NULL);
+ new_node->val = arr[i];
+ new_node->next = list;
+ list = new_node;
+ }
+ return list;
+}
+
+struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
+ struct ListNode* l3 = NULL;
+ struct ListNode* tail_node = NULL;
+ int carry = 0;
+ while (l1 != NULL || l2 != NULL || carry != 0) {
+ struct ListNode* new_node = malloc(sizeof(struct ListNode));
+ assert(new_node != NULL);
+ int sum = carry;
+ if (l1 != NULL) {
+ sum += l1->val;
+ l1 = l1->next;
+ }
+ if (l2 != NULL) {
+ sum += l2->val;
+ l2 = l2->next;
+ }
+ carry = sum / 10;
+ new_node->val = sum % 10;
+ new_node->next = NULL;
+ if (tail_node == NULL) {
+ l3 = new_node;
+ tail_node = new_node;
+ } else {
+ tail_node->next = new_node;
+ tail_node = new_node;
+ }
+ }
+ return l3;
+}
+
+int main() {
+ int arr1[] = {2, 4, 3};
+ int arr2[] = {5, 6, 4};
+ struct ListNode* l1 = listFromArray(arr1, 3);
+ struct ListNode* l2 = listFromArray(arr2, 3);
+ struct ListNode* l3 = addTwoNumbers(l1, l2);
+ while (l3 != NULL) {
+ printf("%d, ", l3->val);
+ l3 = l3->next;
+ }
+ printf("\n");
+
+ return 0;
+}
diff --git a/leetcode/cpp/0003.longest-substring-without-repeating-characters/CMakeLists.txt b/leetcode/cpp/0003.longest-substring-without-repeating-characters/CMakeLists.txt
new file mode 100644
index 00000000..9b295693
--- /dev/null
+++ b/leetcode/cpp/0003.longest-substring-without-repeating-characters/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0003-longest-substring-without-repeating-characters
+ main.c
+ )
diff --git a/leetcode/cpp/0003.longest-substring-without-repeating-characters/main.c b/leetcode/cpp/0003.longest-substring-without-repeating-characters/main.c
new file mode 100644
index 00000000..87ceec72
--- /dev/null
+++ b/leetcode/cpp/0003.longest-substring-without-repeating-characters/main.c
@@ -0,0 +1,52 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+int lengthOfLongestSubstring(char* s) {
+ int n = strlen(s);
+ if (n == 0) {
+ return 0;
+ }
+ if (n == 1) {
+ return 1;
+ }
+
+ int max_val = 1;
+ int len = 0;
+
+ for (int i = 0; i < n; ++i) {
+ for (int j = i + 1; j < n; ++j) {
+ if (s[i] == s[j]) {
+ break;
+ }
+
+ len = j - i - 1;
+ if (max_val < len) {
+ max_val = len;
+ }
+ }
+ }
+ return max_val;
+}
+
+void checkSolutioin(char* s, int exp) {
+ int out = lengthOfLongestSubstring(s);
+ printf("out: %d, exp: %d\n", out, exp);
+ assert(out == exp);
+}
+
+int main() {
+ char* s1 = "abcabcbb";
+ checkSolutioin(s1, 3);
+ char* s2 = "bbbbbb";
+ checkSolutioin(s2, 1);
+ char* s3 = "pwwkew";
+ checkSolutioin(s3, 3);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0005.longest-palindromic-substring/CMakeLists.txt b/leetcode/cpp/0005.longest-palindromic-substring/CMakeLists.txt
new file mode 100644
index 00000000..2b086e2b
--- /dev/null
+++ b/leetcode/cpp/0005.longest-palindromic-substring/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0005-longest-palindromic-substring
+ main.c
+ )
diff --git a/leetcode/cpp/0005.longest-palindromic-substring/main.c b/leetcode/cpp/0005.longest-palindromic-substring/main.c
new file mode 100644
index 00000000..65945e42
--- /dev/null
+++ b/leetcode/cpp/0005.longest-palindromic-substring/main.c
@@ -0,0 +1,11 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0007.reverse-integer/CMakeLists.txt b/leetcode/cpp/0007.reverse-integer/CMakeLists.txt
new file mode 100644
index 00000000..05fdf0e0
--- /dev/null
+++ b/leetcode/cpp/0007.reverse-integer/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0007-reverse-integer
+ main.c
+ )
diff --git a/leetcode/cpp/0007.reverse-integer/main.c b/leetcode/cpp/0007.reverse-integer/main.c
new file mode 100644
index 00000000..1c63e483
--- /dev/null
+++ b/leetcode/cpp/0007.reverse-integer/main.c
@@ -0,0 +1,39 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+#include
+
+int reverse(int x) {
+ int rev = 0;
+ while (x != 0) {
+ if (rev > INT_MAX / 10 || rev < INT_MIN / 10) {
+ return 0;
+ }
+ rev = rev * 10 + x % 10;
+ x /= 10;
+ }
+
+ return rev;
+}
+
+void checkSolution(int x, int expected_rev_x) {
+ int rev_x = reverse(x);
+ printf("x: %d, rev_x: %d, expected: %d\n", x, rev_x, expected_rev_x);
+ assert(rev_x == expected_rev_x);
+}
+
+int main() {
+ checkSolution(123, 321);
+ checkSolution(-123, -321);
+ checkSolution(120, 21);
+ checkSolution(1534236469, 0);
+ checkSolution(-2147483648, 0);
+ checkSolution(-2147483412, -2143847412);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0008.string-to-integer-atoi/CMakeLists.txt b/leetcode/cpp/0008.string-to-integer-atoi/CMakeLists.txt
new file mode 100644
index 00000000..b83f2dbd
--- /dev/null
+++ b/leetcode/cpp/0008.string-to-integer-atoi/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0008-string-to-integer-atoi
+ main.c
+ )
diff --git a/leetcode/cpp/0008.string-to-integer-atoi/main.c b/leetcode/cpp/0008.string-to-integer-atoi/main.c
new file mode 100644
index 00000000..fcef919d
--- /dev/null
+++ b/leetcode/cpp/0008.string-to-integer-atoi/main.c
@@ -0,0 +1,79 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+int myAtoi(char* s) {
+ char* ptr = s;
+ long val = 0;
+ int is_negative = 0;
+ int has_sign = 0;
+ int digit_count = 0;
+ const long kIntMax = -(long)INT_MIN;
+
+ while (*ptr != '\0') {
+ char c = *ptr;
+ ptr += 1;
+
+ if (c == ' ' && has_sign == 0 && digit_count == 0) {
+ continue;
+ }
+
+ if (c == '-' || c == '+') {
+ if (has_sign || digit_count) {
+ // Invalid sign.
+ break;
+ }
+
+ has_sign = 1;
+ if (c == '-') {
+ is_negative = 1;
+ }
+ } else if (c >= '0' && c <= '9') {
+ int digit = c - '0';
+ val = val * 10 + digit;
+ digit_count += 1;
+ // FIXME(shaohua): overflow
+ if (val > kIntMax) {
+ val = kIntMax;
+ }
+ } else {
+ // End of valid digits.
+ break;
+ }
+ }
+
+ if (val >= kIntMax) {
+ if (is_negative) {
+ val = INT_MIN;
+ } else {
+ val = INT_MAX;
+ }
+ } else if (is_negative) {
+ val = -val;
+ }
+
+ return val;
+}
+
+void checkSolution(char* s, int exp) {
+ int val = myAtoi(s);
+ printf("val: %d, exp: %d\n", val, exp);
+ assert(val == exp);
+}
+
+int main() {
+ checkSolution("42", 42);
+ checkSolution(" -42", -42);
+ checkSolution("4193 with words", 4193);
+ checkSolution("-91283472332", -2147483648);
+ checkSolution(" +0 123", 0);
+ checkSolution("20000000000000000000", 2147483647);
+ checkSolution("-2147483647", -2147483647);
+ checkSolution("-5-", -5);
+ return 0;
+}
diff --git a/leetcode/cpp/0011.container-with-most-water/CMakeLists.txt b/leetcode/cpp/0011.container-with-most-water/CMakeLists.txt
new file mode 100644
index 00000000..232fd292
--- /dev/null
+++ b/leetcode/cpp/0011.container-with-most-water/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0011-container-with-most-water
+ main.c
+ )
diff --git a/leetcode/cpp/0011.container-with-most-water/main.c b/leetcode/cpp/0011.container-with-most-water/main.c
new file mode 100644
index 00000000..ee0d805d
--- /dev/null
+++ b/leetcode/cpp/0011.container-with-most-water/main.c
@@ -0,0 +1,44 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+int maxArea(int* height, int heightSize) {
+ assert(heightSize >= 2);
+ int max_area = 0;
+ int left = 0;
+ int right = heightSize - 1;
+ int area = 0;
+
+ while (left < right) {
+ if (height[left] < height[right]) {
+ area = (right - left) * height[left];
+ left += 1;
+ } else {
+ area = (right - left) * height[right];
+ right -= 1;
+ }
+ max_area = (max_area < area) ? area : max_area;
+ }
+
+ return max_area;
+}
+
+void checkSolution(int* height, int heightSize, int expected_area) {
+ int area = maxArea(height, heightSize);
+ printf("area: %d, expected: %d\n", area, expected_area);
+ assert(area == expected_area);
+}
+
+int main() {
+ int heigh1[] = {1, 8, 6, 2, 5, 4, 8, 3, 7};
+ checkSolution(heigh1, sizeof(heigh1) / sizeof(heigh1[0]), 49);
+
+ int height2[] = {1, 1};
+ checkSolution(height2, sizeof(height2) / sizeof(height2[0]), 1);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0014.longest-common-prefix/CMakeLists.txt b/leetcode/cpp/0014.longest-common-prefix/CMakeLists.txt
new file mode 100644
index 00000000..d4dc19b0
--- /dev/null
+++ b/leetcode/cpp/0014.longest-common-prefix/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0014-longest-common-prefix
+ main.c
+ )
diff --git a/leetcode/cpp/0014.longest-common-prefix/main.c b/leetcode/cpp/0014.longest-common-prefix/main.c
new file mode 100644
index 00000000..27d86d02
--- /dev/null
+++ b/leetcode/cpp/0014.longest-common-prefix/main.c
@@ -0,0 +1,50 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+char* longestCommonPrefix(char** strs, int strsSize) {
+ int index = 0;
+ int stop = 0;
+ while (!stop) {
+ if (strs[0][index] == '\0') {
+ break;
+ }
+
+ for (int i = 1; i < strsSize; ++i) {
+ if (strs[0][index] != strs[i][index]) {
+ stop = 1;
+ break;
+ }
+ }
+ if (!stop) {
+ index += 1;
+ }
+ }
+
+ char* out = (char*)malloc(index + 1);
+ assert(out);
+ memcpy(out, strs[0], index);
+ out[index] = '\0';
+ return out;
+}
+
+void checkSolutioin(char** strs, int strsSize, char* expected) {
+ char* got = longestCommonPrefix(strs, strsSize);
+ printf("got: %s, expected: %s\n", got, expected);
+ assert(strcmp(got, expected));
+}
+
+int main() {
+ char* strs[] = {"flower","flow","flight"};
+ checkSolutioin(strs, 3, "fl");
+
+ char* strs2[] = {"dog","racecar","car"};
+ checkSolutioin(strs2, 3, "");
+
+ return 0;
+}
diff --git a/leetcode/cpp/0015.3sum/CMakeLists.txt b/leetcode/cpp/0015.3sum/CMakeLists.txt
new file mode 100644
index 00000000..05d40b98
--- /dev/null
+++ b/leetcode/cpp/0015.3sum/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0015-3sum
+ main.cpp
+ )
diff --git a/leetcode/cpp/0015.3sum/main.cpp b/leetcode/cpp/0015.3sum/main.cpp
new file mode 100644
index 00000000..cf4276c6
--- /dev/null
+++ b/leetcode/cpp/0015.3sum/main.cpp
@@ -0,0 +1,72 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+
+#include
+#include
+#include
+
+class Solution {
+ public:
+ static
+ std::vector> threeSum(std::vector& nums) {
+ std::sort(nums.begin(), nums.end());
+ std::vector> result;
+
+ for (size_t i = 0; i < nums.size() - 2; ++i) {
+ if (nums[i] > 0) {
+ break;
+ }
+ if (i > 0 && nums[i] == nums[i-1]) {
+ continue;
+ }
+
+ int left = i + 1;
+ int right = nums.size() - 1;
+ int first = -nums[i];
+
+ while (left < right) {
+ int sum = nums[left] + nums[right];
+ if (sum < first) {
+ left += 1;
+ } else if (sum > first) {
+ right -= 1;
+ } else {
+ result.push_back({nums[i], nums[left], nums[right]});
+ while (left < right && nums[left] == nums[left + 1]) {
+ left += 1;
+ }
+ while (right > left && nums[right] == nums[right - 1]) {
+ right -= 1;
+ }
+ left += 1;
+ right -= 1;
+ }
+ }
+ }
+
+ return result;
+ }
+};
+
+void checkSolution(int* nums, int numsSize) {
+ std::vector vector(nums, nums + numsSize);
+ const auto result = Solution::threeSum(vector);
+ for (const auto& entry : result) {
+ printf("[%d, %d, %d]\n", entry[0], entry[1], entry[2]);
+ }
+}
+
+int main() {
+ int arr1[] = {-1, 0, 1, 2, -1, -4};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ int arr2[ ] =
+ 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+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0016.3sum-closest/CMakeLists.txt b/leetcode/cpp/0016.3sum-closest/CMakeLists.txt
new file mode 100644
index 00000000..6a4c3bf7
--- /dev/null
+++ b/leetcode/cpp/0016.3sum-closest/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0016-3sum-closest
+ main.cpp
+ )
diff --git a/leetcode/cpp/0016.3sum-closest/main.cpp b/leetcode/cpp/0016.3sum-closest/main.cpp
new file mode 100644
index 00000000..a553bece
--- /dev/null
+++ b/leetcode/cpp/0016.3sum-closest/main.cpp
@@ -0,0 +1,59 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+
+#include
+#include
+
+class Solution {
+ public:
+ static
+ int threeSumClosest(std::vector& nums, int target) {
+ std::sort(nums.begin(), nums.end());
+ int min_diff = INT_MAX;
+ int result = 0;
+
+ for (size_t i = 0; i < nums.size() - 2; ++i) {
+ int left = i + 1;
+ int right = nums.size() - 1;
+ int first = nums[i];
+
+ while (left < right) {
+ int sum = first + nums[left] + nums[right];
+ if (sum == target) {
+ return sum;
+ }
+
+ int d = std::abs(sum - target);
+ if (d < min_diff) {
+ min_diff = d;
+ result = sum;
+ }
+ if (sum < target) {
+ left += 1;
+ } else if (sum > target) {
+ right -= 1;
+ }
+ }
+ }
+
+ return result;
+ }
+
+};
+
+void checkSolution(int* nums, int numsSize, int target, int expectedSum) {
+ std::vector vector(nums, nums + numsSize);
+ int sum = Solution::threeSumClosest(vector, target);
+ assert(sum == expectedSum);
+}
+
+int main() {
+ int arr1[] = {-1, 2, 1, -4};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 1, 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0018.4sum/CMakeLists.txt b/leetcode/cpp/0018.4sum/CMakeLists.txt
new file mode 100644
index 00000000..051c4881
--- /dev/null
+++ b/leetcode/cpp/0018.4sum/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0018-4sum
+ main.cpp
+ )
diff --git a/leetcode/cpp/0018.4sum/main.cpp b/leetcode/cpp/0018.4sum/main.cpp
new file mode 100644
index 00000000..48cfe3bc
--- /dev/null
+++ b/leetcode/cpp/0018.4sum/main.cpp
@@ -0,0 +1,82 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+
+#include
+#include
+#include
+
+class Solution {
+public:
+ static
+ std::vector> fourSum(std::vector& nums, int target) {
+ int len = nums.size();
+ std::vector> result;
+ std::sort(nums.begin(), nums.end());
+
+ for (int i = 0; i < len-3; ++i) {
+ if (i > 0 && nums[i] == nums[i-1]) {
+ continue;
+ }
+
+ for (int j = i+1; j < len-2; ++j) {
+ if (j > i + 1 && nums[j] == nums[j-1]) {
+ continue;
+ }
+
+ int left = j + 1;
+ int right = len - 1;
+ long remains = (long)target - (long)nums[i] - (long)nums[j];
+ while (left < right) {
+ long sum = (long)nums[left] + (long)nums[right];
+ if (remains < sum) {
+ right -= 1;
+ } else if (remains > sum) {
+ left += 1;
+ } else {
+ result.push_back({nums[i], nums[j], nums[left], nums[right]});
+ while (left < right && nums[left] == nums[left+1]) {
+ left += 1;
+ }
+ while (left < right && nums[right] == nums[right-1]) {
+ right -= 1;
+ }
+ left += 1;
+ right -= 1;
+ }
+ }
+ }
+ }
+
+ return result;
+ }
+};
+
+void checkSolution(int* arr, int arr_len, int target, int out_len) {
+ std::vector nums{arr, arr + arr_len};
+ std::vector> result = Solution::fourSum(nums, target);
+ for (const auto& entry : result) {
+ printf("[%d, %d, %d, %d]\n", entry[0], entry[1], entry[2], entry[3]);
+ }
+ printf("result size: %d, expected; %d\n", result.size(), out_len);
+ assert(result.size() == out_len);
+}
+
+int main() {
+ int arr1[] = {1, 0, -1, 0, -2, 2};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 0, 3);
+
+ int arr2[] = {2, 2, 2, 2, 2};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 8, 1);
+
+ int arr3[] = {2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2};
+ checkSolution(arr3, sizeof(arr3) / sizeof(arr3[0]), 8, 1);
+
+ int arr4[] = {1, -2, -5, -4, -3, 3, 3, 5};
+ checkSolution(arr4, sizeof(arr4) / sizeof(arr4[0]), -11, 1);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0019.remove-nth-node-from-end-of-list/CMakeLists.txt b/leetcode/cpp/0019.remove-nth-node-from-end-of-list/CMakeLists.txt
new file mode 100644
index 00000000..a1c73c62
--- /dev/null
+++ b/leetcode/cpp/0019.remove-nth-node-from-end-of-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0019-remove-nth-node-from-end-of-list
+ main.c
+ )
diff --git a/leetcode/cpp/0019.remove-nth-node-from-end-of-list/main.c b/leetcode/cpp/0019.remove-nth-node-from-end-of-list/main.c
new file mode 100644
index 00000000..2dfbc678
--- /dev/null
+++ b/leetcode/cpp/0019.remove-nth-node-from-end-of-list/main.c
@@ -0,0 +1,143 @@
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNodeNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNodeNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static int listSize(struct ListNode* list) {
+ int size = 0;
+ while (list != NULL) {
+ size += 1;
+ list = list->next;
+ }
+ return size;
+}
+
+static struct ListNode* removeNthFromEnd(struct ListNode* head, int n) {
+ assert(head != NULL);
+ assert(n >= 0);
+
+ struct ListNode* tmp = NULL;
+ int size = listSize(head);
+ assert(n <= size);
+
+ if (size == n) {
+ // Remove head node.
+ tmp = head;
+ head = head->next;
+ free(tmp);
+ return head;
+ }
+
+ int index = 0;
+ struct ListNode* head_clone = head;
+ while (index + 1 < size - n && head != NULL) {
+ head = head->next;
+ index += 1;
+ }
+ assert(head != NULL);
+ if (head->next != NULL) {
+ tmp = head->next;
+ head->next = head->next->next;
+ free(tmp);
+ }
+
+ return head_clone;
+}
+
+static struct ListNode* removeNthFromEnd2Helper(struct ListNode* current, int n, int* count) {
+ // End of list.
+ if (current == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* next = removeNthFromEnd2Helper(current->next, n, count);
+ *count += 1;
+ if (*count == n) {
+ free(current);
+ return next;
+ }
+
+ current->next = next;
+ return current;
+}
+
+static struct ListNode* removeNthFromEnd2(struct ListNode* head, int n) {
+ int count = 0;
+ return removeNthFromEnd2Helper(head, n, &count);
+}
+
+static struct ListNode* removeNthFromEnd3(struct ListNode* head, int n) {
+ assert(n >= 0);
+ if (head == NULL) {
+ return NULL;
+ }
+
+ // Used for counting.
+ struct ListNode* fast = head;
+ struct ListNode* slow = head;
+
+ for (int i = 0; i < n; ++i) {
+ fast = fast->next;
+ }
+ if (fast == NULL) {
+ return NULL;
+ }
+
+ while (fast->next != NULL) {
+ fast = fast->next;
+ slow = slow->next;
+ }
+ struct ListNode* tmp = slow->next;
+ assert(tmp != NULL);
+ slow->next = slow->next->next;
+ free(tmp);
+ return head;
+}
+
+static void checkSolution(int arr[], int arr_len, int target) {
+ struct ListNode* l1 = listFromArray(arr, arr_len);
+ //struct ListNode* l2 = removeNthFromEnd(l1, target);
+ struct ListNode* l2 = removeNthFromEnd2(l1, target);
+ //struct ListNode* l2 = removeNthFromEnd3(l1, target);
+ while (l2 != NULL) {
+ printf("%d, ", l2->val);
+ l2 = l2->next;
+ }
+ printf("\n");
+}
+
+int main() {
+ int arr1[] = {1, 2, 3, 4, 5};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 2);
+
+ int arr2[] = {1};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 1);
+
+ int arr3[] = {1, 2};
+ checkSolution(arr3, sizeof(arr3) / sizeof(arr3[0]), 1);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0020.valid-parentheses/CMakeLists.txt b/leetcode/cpp/0020.valid-parentheses/CMakeLists.txt
new file mode 100644
index 00000000..540e3485
--- /dev/null
+++ b/leetcode/cpp/0020.valid-parentheses/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0020-valid-parentheses
+ main.cpp
+ )
diff --git a/leetcode/cpp/0020.valid-parentheses/main.cpp b/leetcode/cpp/0020.valid-parentheses/main.cpp
new file mode 100644
index 00000000..aa98be98
--- /dev/null
+++ b/leetcode/cpp/0020.valid-parentheses/main.cpp
@@ -0,0 +1,43 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+
+#include
+#include
+
+bool isValid(std::string s) {
+ std::stack stack;
+
+ for (char c : s) {
+ if (c == '(' || c == '[' || c == '{') {
+ stack.push(c);
+ } else {
+ if (stack.empty()) {
+ return false;
+ }
+ char old_c = stack.top();
+ stack.pop();
+ if ((old_c == '(' && c != ')') ||
+ (old_c == '[' && c != ']') ||
+ (old_c == '{' && c != '}')) {
+ return false;
+ }
+ }
+ }
+
+ return stack.empty();
+}
+
+void checkSolution(char* s, bool exp_valid) {
+ bool is_valid = isValid(s);
+ assert(is_valid == exp_valid);
+}
+
+int main() {
+ checkSolution("()", true);
+ checkSolution("()[]{}", true);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0021.merge-two-sorted-lists/CMakeLists.txt b/leetcode/cpp/0021.merge-two-sorted-lists/CMakeLists.txt
new file mode 100644
index 00000000..cb2b96ec
--- /dev/null
+++ b/leetcode/cpp/0021.merge-two-sorted-lists/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0021-merge-two-sorted-lists
+ main.c
+ )
diff --git a/leetcode/cpp/0021.merge-two-sorted-lists/main.c b/leetcode/cpp/0021.merge-two-sorted-lists/main.c
new file mode 100644
index 00000000..694667fd
--- /dev/null
+++ b/leetcode/cpp/0021.merge-two-sorted-lists/main.c
@@ -0,0 +1,93 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode *next;
+};
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = arr[i];
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static
+struct ListNode* listReverse(struct ListNode* list) {
+ assert(list != NULL);
+ struct ListNode* prev = NULL;
+ struct ListNode* next = NULL;
+ while (list != NULL) {
+ next = list->next;
+ list->next = prev;
+ prev = list;
+ list = next;
+ }
+ return prev;
+}
+
+struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {
+ if (l1 == NULL) {
+ return l2;
+ }
+ if (l2 == NULL) {
+ return l1;
+ }
+ l1 = listReverse(l1);
+ l2 = listReverse(l2);
+
+ struct ListNode* l3 = NULL;
+ struct ListNode* node = NULL;
+
+ while (l1 != NULL && l2 != NULL) {
+ if (l1->val >= l2->val) {
+ node = l1;
+ l1 = l1->next;
+ } else {
+ node = l2;
+ l2 = l2->next;
+ }
+ node->next = l3;
+ l3 = node;
+ }
+ while (l1 != NULL) {
+ node = l1;
+ l1 = l1->next;
+ node->next = l3;
+ l3 = node;
+ }
+ while (l2 != NULL) {
+ node = l2;
+ l2 = l2->next;
+ node->next = l3;
+ l3 = node;
+ }
+
+ return l3;
+}
+
+int main() {
+ int arr1[] = {1, 2, 4};
+ int arr2[] = {1, 3, 4};
+ struct ListNode* l1 = listFromArray(arr1, sizeof(arr1) / sizeof(arr1[0]));
+ struct ListNode* l2 = listFromArray(arr2, sizeof(arr2) / sizeof(arr2[0]));
+ struct ListNode* l3 = mergeTwoLists(l1, l2);
+ while (l3 != NULL) {
+ printf("%d, ", l3->val);
+ l3 = l3->next;
+ }
+ printf("\n");
+
+ return 0;
+}
diff --git a/leetcode/cpp/0025.reverse-nodes-in-k-group/CMakeLists.txt b/leetcode/cpp/0025.reverse-nodes-in-k-group/CMakeLists.txt
new file mode 100644
index 00000000..79e865c3
--- /dev/null
+++ b/leetcode/cpp/0025.reverse-nodes-in-k-group/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0025.reverse-nodes-in-k-group
+ main.c
+ )
diff --git a/leetcode/cpp/0026.remove-duplicates-from-sorted-array/CMakeLists.txt b/leetcode/cpp/0026.remove-duplicates-from-sorted-array/CMakeLists.txt
new file mode 100644
index 00000000..ca808660
--- /dev/null
+++ b/leetcode/cpp/0026.remove-duplicates-from-sorted-array/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0026-remove-duplicates-from-sorted-array
+ main.c
+ )
diff --git a/leetcode/cpp/0026.remove-duplicates-from-sorted-array/main.c b/leetcode/cpp/0026.remove-duplicates-from-sorted-array/main.c
new file mode 100644
index 00000000..2aebc3b8
--- /dev/null
+++ b/leetcode/cpp/0026.remove-duplicates-from-sorted-array/main.c
@@ -0,0 +1,41 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+int removeDuplicates(int* nums, int numsSize) {
+ int* slow = nums;
+ int* fast = nums;
+
+ for (int i = 0; i < numsSize; ++i) {
+ // Skip duplicate elements
+ while (i+1 < numsSize && fast[i] == fast[i+1]) {
+ i += 1;
+ }
+ *slow = fast[i];
+ slow += 1;
+ }
+
+ return slow - nums;
+}
+
+void checkSolution(int* nums, int numsSize) {
+ int k = removeDuplicates(nums, numsSize);
+ for (int i = 0; i < k; ++i) {
+ printf("%d, ", nums[i]);
+ }
+ printf("\n");
+}
+
+int main() {
+ int arr1[] = {0,0,1,1,1,2,2,3,3,4};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ int arr2[] = {1, 1, 2};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0027.remove-element/CMakeLists.txt b/leetcode/cpp/0027.remove-element/CMakeLists.txt
new file mode 100644
index 00000000..1d5e168c
--- /dev/null
+++ b/leetcode/cpp/0027.remove-element/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0027-remove-element
+ main.c
+ )
diff --git a/leetcode/cpp/0027.remove-element/main.c b/leetcode/cpp/0027.remove-element/main.c
new file mode 100644
index 00000000..78881098
--- /dev/null
+++ b/leetcode/cpp/0027.remove-element/main.c
@@ -0,0 +1,39 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+int removeElement(int* nums, int numsSize, int val) {
+ for (int i = 0; i < numsSize; /* empty */) {
+ if (nums[i] == val) {
+ // Implements swap_remove()
+ nums[i] = nums[numsSize - 1];
+ numsSize -= 1;
+ } else {
+ i += 1;
+ }
+ }
+ return numsSize;
+}
+
+void checkSolution(int* nums, int numsSize, int val, int expected_k) {
+ int k = removeElement(nums, numsSize, val);
+ for (int i = 0; i < k; ++i) {
+ printf("%d, ", nums[i]);
+ }
+ printf("\n");
+ assert(k == expected_k);
+}
+
+int main() {
+ int arr1[] = {0, 1, 2, 2, 3, 0, 4, 2};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 2, 5);
+
+ int arr2[] = {3, 2, 2, 3};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 3, 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0031.next-permutation/CMakeLists.txt b/leetcode/cpp/0031.next-permutation/CMakeLists.txt
new file mode 100644
index 00000000..df8bb6bc
--- /dev/null
+++ b/leetcode/cpp/0031.next-permutation/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0031-next-permutation
+ main.c
+ )
diff --git a/leetcode/cpp/0031.next-permutation/main.c b/leetcode/cpp/0031.next-permutation/main.c
new file mode 100644
index 00000000..e69de29b
diff --git a/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/CMakeLists.txt b/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/CMakeLists.txt
new file mode 100644
index 00000000..19cdd24c
--- /dev/null
+++ b/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0034-find-first-and-last-position-of-element-in-sorted-array
+ main.cpp
+ )
diff --git a/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/main.cpp b/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/main.cpp
new file mode 100644
index 00000000..9362b060
--- /dev/null
+++ b/leetcode/cpp/0034.find-first-and-last-position-of-element-in-sorted-array/main.cpp
@@ -0,0 +1,60 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+
+#include
+
+class Solution {
+ public:
+ static
+ std::vector searchRange(std::vector& nums, int target) {
+ std::vector range;
+ range.push_back(-1);
+ range.push_back(-1);
+ if (nums.empty()) {
+ return range;
+ }
+
+ int left = 0;
+ int right = nums.size() - 1;
+
+ while (left <= right) {
+ printf("left: %d, right: %d\n", left, right);
+ int middle = left + (right - left) / 2;
+ if (nums[middle] == target) {
+ for (int i = middle; i >= 0 && nums[i] == target; --i) {
+ range[0] = i;
+ }
+ for (int i = middle; i < nums.size() && nums[i] == target; ++i) {
+ range[1] = i;
+ }
+ break;
+ } else if (nums[middle] < target) {
+ left = middle + 1;
+ } else {
+ right = middle - 1;
+ }
+ }
+
+ return range;
+ }
+};
+
+void checkSolution(int* nums, int numsSize, int target, int left, int right) {
+ std::vector vec{nums, nums + numsSize};
+ std::vector range = Solution::searchRange(vec, target);
+ assert(range[0] == left);
+ assert(range[1] == right);
+}
+
+int main() {
+ int arr1[] = {5,7,7,8,8,10};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 8, 3, 4);
+
+ int arr2[] = {1};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 1, 0, 0);
+ return 0;
+}
diff --git a/leetcode/cpp/0035.search-insert-position/CMakeLists.txt b/leetcode/cpp/0035.search-insert-position/CMakeLists.txt
new file mode 100644
index 00000000..b927e51b
--- /dev/null
+++ b/leetcode/cpp/0035.search-insert-position/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0035-search-insert-position
+ main.c
+ )
diff --git a/leetcode/cpp/0035.search-insert-position/main.c b/leetcode/cpp/0035.search-insert-position/main.c
new file mode 100644
index 00000000..b6b32048
--- /dev/null
+++ b/leetcode/cpp/0035.search-insert-position/main.c
@@ -0,0 +1,48 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+// Binary search
+int searchInsert(int* nums, int numsSize, int target) {
+ if (nums[numsSize - 1] < target) {
+ return numSize;
+ }
+
+ int left = 0;
+ int right = numsSize - 1;
+ int middle = 0;
+ while (left < right) {
+ middle = left + (right - left) / 2;
+ if (nums[middle] == target) {
+ return middle;
+ }
+ if (nums[middle] > target) {
+ right = middle - 1;
+ } else {
+ left = middle + 1;
+ }
+ }
+ return right;
+}
+
+void checkSolution(int* nums, int numsSize, int target, int expected) {
+ int out = searchInsert(nums, numsSize, target);
+ printf("out: %d, expected: %d\n", out, expected);
+ assert(out == expected);
+}
+int main() {
+ int arr1[] = {1, 3, 5, 6};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 5, 2);
+
+ int arr2[] = {1, 3, 5, 6};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 2, 1);
+
+ int arr3[] = {1, 3, 5, 6};
+ checkSolution(arr3, sizeof(arr3) / sizeof(arr3[0]), 7, 4);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0053.maximum-subarray/CMakeLists.txt b/leetcode/cpp/0053.maximum-subarray/CMakeLists.txt
new file mode 100644
index 00000000..cce5f150
--- /dev/null
+++ b/leetcode/cpp/0053.maximum-subarray/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0053-maximum-subarray
+ main.c
+ )
diff --git a/leetcode/cpp/0053.maximum-subarray/main.c b/leetcode/cpp/0053.maximum-subarray/main.c
new file mode 100644
index 00000000..e69de29b
diff --git a/leetcode/cpp/0061.rotate-list/CMakeLists.txt b/leetcode/cpp/0061.rotate-list/CMakeLists.txt
new file mode 100644
index 00000000..82eb9c2c
--- /dev/null
+++ b/leetcode/cpp/0061.rotate-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0061-rotate-list
+ main.c
+ )
diff --git a/leetcode/cpp/0061.rotate-list/main.c b/leetcode/cpp/0061.rotate-list/main.c
new file mode 100644
index 00000000..e545fc8f
--- /dev/null
+++ b/leetcode/cpp/0061.rotate-list/main.c
@@ -0,0 +1,138 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static void listFree(struct ListNode* list) {
+ assert(list != NULL);
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+static int listSize(struct ListNode* list) {
+ assert(list != NULL);
+ int len = 0;
+ while (list != NULL) {
+ len += 1;
+ list = list->next;
+ }
+ return len;
+}
+
+struct ListNode* rotateRight(struct ListNode* head, int k) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ assert(k >= 0);
+
+ //const int len = listSize(head);
+ int len = 1;
+ struct ListNode* tail = head;
+ while (tail != NULL && tail->next != NULL) {
+ tail = tail->next;
+ len += 1;
+ }
+
+ k = len - (k % len);
+ if (k == 0) {
+ return head;
+ }
+
+ // Connect tail to head.
+ tail->next = head;
+
+ // Count node from head to tail.
+ while (k > 0) {
+ head = head->next;
+ tail = tail->next;
+ k -= 1;
+ }
+ // Break the ring at k point.
+ tail->next = NULL;
+
+ return head;
+}
+
+struct ListNode* rotateRight2(struct ListNode* head, int k) {
+ if (head == NULL) {
+ return NULL;
+ }
+ assert(k >= 0);
+
+ struct ListNode* fast = head;
+ struct ListNode* slow = head;
+ // FIXME(Shaohua): k might > len
+ while (k > 0) {
+ fast = fast->next;
+ k -= 1;
+ }
+
+ while (fast != NULL && fast->next != NULL) {
+ fast = fast->next;
+ slow = slow->next;
+ }
+ // Connect tail to head node.
+ fast->next = head;
+ // Now slow is the new tail node.
+ head = slow->next;
+ slow->next = NULL;
+
+ return head;
+}
+
+static void checkResult(int arr[], int len, int k) {
+ struct ListNode* head = listFromArray(arr, len);
+ struct ListNode* new_head = rotateRight(head, k);
+ //struct ListNode* new_head = rotateRight2(head, k);
+ head = new_head;
+ while (head != NULL) {
+ printf("%d, ", head->val);
+ head = head->next;
+ }
+ printf("\n");
+ free(new_head);
+}
+
+int main() {
+ int arr1[] = {1,2,3,4,5};
+ checkResult(arr1, sizeof(arr1) / sizeof(arr1[0]), 2);
+
+ int arr2[] = {1,2};
+ checkResult(arr2, sizeof(arr2) / sizeof(arr2[0]), 0);
+
+ int arr3[] = {1};
+ checkResult(arr3, sizeof(arr3) / sizeof(arr3[0]), 10);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0061.rotate-list/time.md b/leetcode/cpp/0061.rotate-list/time.md
new file mode 100644
index 00000000..689fdcde
--- /dev/null
+++ b/leetcode/cpp/0061.rotate-list/time.md
@@ -0,0 +1,3 @@
+
+# Time
+- 00:32:30
diff --git a/leetcode/cpp/0062.unique-paths/CMakeLists.txt b/leetcode/cpp/0062.unique-paths/CMakeLists.txt
new file mode 100644
index 00000000..f1b713d6
--- /dev/null
+++ b/leetcode/cpp/0062.unique-paths/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0062-unique-paths
+ main.c
+ )
diff --git a/leetcode/cpp/0066.plus-one/CMakeLists.txt b/leetcode/cpp/0066.plus-one/CMakeLists.txt
new file mode 100644
index 00000000..2bf7ec53
--- /dev/null
+++ b/leetcode/cpp/0066.plus-one/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0066-plus-one
+ main.c
+ )
diff --git a/leetcode/cpp/0066.plus-one/main.c b/leetcode/cpp/0066.plus-one/main.c
new file mode 100644
index 00000000..f05b9bf0
--- /dev/null
+++ b/leetcode/cpp/0066.plus-one/main.c
@@ -0,0 +1,56 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+int* plusOne(int* digits, int digitsSize, int* returnSize) {
+ int carry = 1;
+ int new_val = 0;
+ for (int i = digitsSize - 1; i >= 0; --i) {
+ new_val = carry + digits[i];
+ digits[i] = new_val % 10;
+ carry = new_val / 10;
+ }
+
+ int* out_digits;
+ if (carry != 0) {
+ *returnSize = digitsSize + 1;
+ out_digits = (int*)malloc(*returnSize * sizeof(int));
+ assert(out_digits);
+ memcpy(out_digits + 1, digits, digitsSize * sizeof(int));
+ out_digits[0] = carry;
+ } else {
+ *returnSize = digitsSize;
+ out_digits = (int*)malloc(*returnSize * sizeof(int));
+ assert(out_digits);
+ memcpy(out_digits, digits, digitsSize * sizeof(int));
+ }
+ return out_digits;
+}
+
+void checkSolution(int* digits, int digitsSize, int expectedReturnSize) {
+ int returnSize;
+ int* out_digits = plusOne(digits, digitsSize, &returnSize);
+ assert(returnSize == expectedReturnSize);
+ for (int i = 0; i < returnSize; ++i) {
+ printf("%d, ", out_digits[i]);
+ }
+ printf("\n");
+}
+
+int main() {
+ int arr1[] = {1, 2, 3};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 3);
+
+ int arr2[] = {4, 3, 2, 1};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 4);
+
+ int arr3[] = {9};
+ checkSolution(arr3, sizeof(arr3) / sizeof(arr3[0]), 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0070.climbing-stairs/CMakeLists.txt b/leetcode/cpp/0070.climbing-stairs/CMakeLists.txt
new file mode 100644
index 00000000..8d9aa2e4
--- /dev/null
+++ b/leetcode/cpp/0070.climbing-stairs/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0070-climbing-stairs
+ main.c
+ )
diff --git a/leetcode/cpp/0070.climbing-stairs/main.c b/leetcode/cpp/0070.climbing-stairs/main.c
new file mode 100644
index 00000000..5c967b80
--- /dev/null
+++ b/leetcode/cpp/0070.climbing-stairs/main.c
@@ -0,0 +1,41 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+int climbStairs(int n) {
+ if (n == 0 || n == 1) {
+ return 1;
+ }
+ return climbStairs(n - 1) + climbStairs(n - 2);
+}
+
+int climbStairs2(int n) {
+ if (n == 0 || n == 1) {
+ return 1;
+ }
+ int f1 = 1;
+ int f2 = 1;
+ int f3 = f1 + f2;
+ for (int i = 2; i <= n; ++i) {
+ f3 = f1 + f2;
+ f1 = f2;
+ f2 = f3;
+ }
+ return f3;
+}
+
+void checkSolution(int n, int expected) {
+ int out = climbStairs2(n);
+ printf("out: %d, exp: %d\n", out, expected);
+ assert(out == expected);
+}
+
+int main() {
+ checkSolution(2, 2);
+ checkSolution(3, 3);
+ return 0;
+}
diff --git a/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/CMakeLists.txt b/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/CMakeLists.txt
new file mode 100644
index 00000000..69000923
--- /dev/null
+++ b/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0082-remove-duplicates-from-sorted-list-ii
+ main.c
+ )
diff --git a/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/main.c b/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/main.c
new file mode 100644
index 00000000..557cd1e3
--- /dev/null
+++ b/leetcode/cpp/0082.remove-duplicates-from-sorted-list-ii/main.c
@@ -0,0 +1,103 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNew(int val) {
+ struct ListNode* list = malloc(sizeof(struct ListNode));
+ assert(list != NULL);
+ list->val = val;
+ list->next = NULL;
+ return list;
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static void listFree(struct ListNode* list) {
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+static struct ListNode* deleteDuplicates(struct ListNode* head) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* current = head;
+ struct ListNode* prev = NULL;
+ struct ListNode* duplicated_node = NULL;
+
+ while (current != NULL) {
+ if (current->next != NULL && current->next->val == current->val) {
+ // Remove current node.
+ if (head == current) {
+ head = current->next;
+ }
+ if (prev != NULL) {
+ prev->next = current->next->next;
+ }
+ duplicated_node = current->next;
+ free(current);
+ current = duplicated_node;
+ // Keep prev position unchanged.
+ } else if (duplicated_node != NULL) {
+ // Remove last duplicated node.
+ assert(current == duplicated_node);
+ if (head == current) {
+ head = current->next;
+ }
+ current = current->next;
+ free(duplicated_node);
+ duplicated_node = NULL;
+ } else {
+ // Go to next node.
+ prev = current;
+ current = current->next;
+ }
+ }
+
+ return head;
+}
+
+static void checkSolution(int arr[], int len) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list_uniq = deleteDuplicates(list);
+ while (list_uniq != NULL) {
+ printf("%d, ", list_uniq->val);
+ list_uniq = list_uniq->next;
+ }
+ printf("\n");
+ listFree(list_uniq);
+}
+
+int main() {
+ // {1, 2, 5}
+ int arr1[] = {1, 2, 3, 3, 4, 4, 5};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ // {2, 3}
+ int arr2[] = {1, 1, 1, 2, 3};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0083.remove-duplicates-from-sorted-list/CMakeLists.txt b/leetcode/cpp/0083.remove-duplicates-from-sorted-list/CMakeLists.txt
new file mode 100644
index 00000000..3c6697e0
--- /dev/null
+++ b/leetcode/cpp/0083.remove-duplicates-from-sorted-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0083-remove-duplicates-from-sorted-list
+ main.c
+ )
diff --git a/leetcode/cpp/0083.remove-duplicates-from-sorted-list/main.c b/leetcode/cpp/0083.remove-duplicates-from-sorted-list/main.c
new file mode 100644
index 00000000..2107dc44
--- /dev/null
+++ b/leetcode/cpp/0083.remove-duplicates-from-sorted-list/main.c
@@ -0,0 +1,83 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNew(int val) {
+ struct ListNode* list = malloc(sizeof(struct ListNode));
+ assert(list != NULL);
+ list->val = val;
+ list->next = NULL;
+ return list;
+}
+
+static void listFree(struct ListNode* list) {
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct ListNode* list;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static struct ListNode* deleteDuplicates(struct ListNode* head) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* current = head;
+ struct ListNode* previous = NULL;
+ while (current != NULL) {
+ if (previous != NULL && previous->val == current->val) {
+ // Remove current node.
+ previous->next = current->next;
+ struct ListNode* tmp = current;
+ current = current->next;
+ free(tmp);
+ } else {
+ previous = current;
+ current = current->next;
+ }
+ }
+
+ return head;
+}
+
+static void checkSolution(int arr[], int len) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list_uniq = deleteDuplicates(list);
+ while (list_uniq != NULL) {
+ printf("%d, ", list_uniq->val);
+ list_uniq = list_uniq->next;
+ }
+ printf("\n");
+
+ listFree(list_uniq);
+}
+
+int main() {
+ int arr1[] = {1, 1, 2};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ int arr2[] = {1, 1, 2, 3, 3};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+ return 0;
+}
diff --git a/leetcode/cpp/0086.partition-list/CMakeLists.txt b/leetcode/cpp/0086.partition-list/CMakeLists.txt
new file mode 100644
index 00000000..93409609
--- /dev/null
+++ b/leetcode/cpp/0086.partition-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0086-partition-list
+ main.c
+ )
diff --git a/leetcode/cpp/0086.partition-list/main.c b/leetcode/cpp/0086.partition-list/main.c
new file mode 100644
index 00000000..1f959232
--- /dev/null
+++ b/leetcode/cpp/0086.partition-list/main.c
@@ -0,0 +1,110 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct ListNode* head = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = head;
+ head = node;
+ }
+
+ return head;
+}
+
+static void listFree(struct ListNode* head) {
+ while (head != NULL) {
+ struct ListNode* tmp = head;
+ head = head->next;
+ free(tmp);
+ }
+}
+
+static struct ListNode* partition(struct ListNode* head, int x) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* small_head = NULL;
+ struct ListNode* small_tail = NULL;
+ struct ListNode* large_head = NULL;
+ struct ListNode* large_tail = NULL;
+ struct ListNode* tmp = NULL;
+ while (head != NULL) {
+ tmp = head;
+ if (tmp->val < x) {
+ if (small_tail == NULL) {
+ small_head = tmp;
+ small_tail = tmp;
+ } else {
+ small_tail->next = tmp;
+ small_tail = tmp;
+ }
+ } else {
+ if (large_tail == NULL) {
+ large_head = tmp;
+ large_tail = tmp;
+ } else {
+ large_tail->next = tmp;
+ large_tail = tmp;
+ }
+ }
+
+ // Go to next node.
+ head = head->next;
+ }
+
+ if (small_tail == NULL) {
+ return large_head;
+ }
+ // Connect two parts.
+ small_tail->next = large_head;
+ if (large_tail != NULL) {
+ large_tail->next = NULL;
+ }
+
+ return small_head;
+}
+
+static void checkSolution(int arr[], int len, int x) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list2 = partition(list, x);
+ list = list2;
+
+ while (list2 != NULL) {
+ printf("%d, ", list2->val);
+ list2 = list2->next;
+ }
+ printf("\n");
+
+ listFree(list);
+}
+
+int main() {
+ int arr1[] = {1,4,3,2,5,2};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 3);
+
+ int arr2[] = {2, 1};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0088.merge-sorted-array/CMakeLists.txt b/leetcode/cpp/0088.merge-sorted-array/CMakeLists.txt
new file mode 100644
index 00000000..1c986a9d
--- /dev/null
+++ b/leetcode/cpp/0088.merge-sorted-array/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0088-merge-sorted-array
+ main.c
+ )
diff --git a/leetcode/cpp/0088.merge-sorted-array/main.c b/leetcode/cpp/0088.merge-sorted-array/main.c
new file mode 100644
index 00000000..182897b0
--- /dev/null
+++ b/leetcode/cpp/0088.merge-sorted-array/main.c
@@ -0,0 +1,38 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+void merge(int* nums1, int nums1Size, int m, int* nums2, int nums2Size, int n) {
+ // Merge from end of nums1
+ int i1 = m - 1;
+ int i2 = n - 1;
+ int index = m + n - 1;
+ while (i1 >= 0 && i2 >= 0) {
+ if (nums1[i1] > nums2[i2]) {
+ nums1[index] = nums1[i1];
+ i1 -= 1;
+ } else {
+ nums1[index] = nums2[i2];
+ i2 -= 1;
+ }
+ index -= 1;
+ }
+ while (i1 >= 0) {
+ nums1[index] = nums1[i1];
+ index -= 1;
+ i1 -= 1;
+ }
+ while (i2 >= 0) {
+ nums1[index] = nums2[i2];
+ index -= 1;
+ i2 -= 1;
+ }
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0092.reverse-linked-list-ii/CMakeLists.txt b/leetcode/cpp/0092.reverse-linked-list-ii/CMakeLists.txt
new file mode 100644
index 00000000..4d5f7f6d
--- /dev/null
+++ b/leetcode/cpp/0092.reverse-linked-list-ii/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0092-reverse-linked-list-ii
+ main.c
+ )
diff --git a/leetcode/cpp/0092.reverse-linked-list-ii/main.c b/leetcode/cpp/0092.reverse-linked-list-ii/main.c
new file mode 100644
index 00000000..dcfc9998
--- /dev/null
+++ b/leetcode/cpp/0092.reverse-linked-list-ii/main.c
@@ -0,0 +1,110 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+static struct ListNode* listNew(int val) {
+ struct ListNode* list = malloc(sizeof(struct ListNode));
+ assert(list != NULL);
+ list->val = val;
+ list->next = NULL;
+ return list;
+}
+
+static struct ListNode* listFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static void listFree(struct ListNode* list) {
+ assert(list != NULL);
+ while (list != NULL) {
+ struct ListNode* node = list;
+ list = list->next;
+ free(node);
+ }
+}
+
+static struct ListNode* reverseBetween(struct ListNode* head, int left, int right) {
+ assert(head != NULL);
+ assert(left >= 1 && left <= right);
+ if (left == right) {
+ return head;
+ }
+ left -= 1;
+ right -= 1;
+
+ struct ListNode* range_prev = NULL;
+ struct ListNode* range_start = NULL;
+ struct ListNode* range_end = NULL;
+ struct ListNode* curr = head;
+ struct ListNode* prev = NULL;
+ struct ListNode* next = NULL;
+
+ int index = 0;
+ while (index < left) {
+ range_prev = curr;
+ curr = curr->next;
+ index += 1;
+ }
+
+ range_start = curr;
+
+ while (index < right) {
+ // switch direction
+ next = curr->next;
+ curr->next = prev;
+ prev = curr;
+ curr = next;
+ index += 1;
+ }
+ range_end = curr;
+ if (range_prev == NULL) {
+ head = range_end;
+ } else {
+ range_prev->next = range_end;
+ }
+ range_start->next = range_end->next;
+ range_end->next = prev;
+
+ return head;
+}
+
+static void checkSolution(int arr[], int len, int left, int right) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* reversed = reverseBetween(list, left, right);
+ list = reversed;
+ while (reversed != NULL) {
+ printf("%d, ", reversed->val);
+ reversed = reversed->next;
+ }
+ printf("\n");
+ listFree(list);
+}
+
+int main() {
+ int arr1[] = {1, 2, 3, 4, 5};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]), 2, 4);
+
+ int arr2[] = {5};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]), 1, 1);
+
+ int arr3[] = {3, 5};
+ checkSolution(arr3, sizeof(arr3) / sizeof(arr3[0]), 1, 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0093.restore-ip-addresses/CMakeLists.txt b/leetcode/cpp/0093.restore-ip-addresses/CMakeLists.txt
new file mode 100644
index 00000000..f240a137
--- /dev/null
+++ b/leetcode/cpp/0093.restore-ip-addresses/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0093-restore-ip-addresses
+ main.cpp
+ )
diff --git a/leetcode/cpp/0093.restore-ip-addresses/main.cpp b/leetcode/cpp/0093.restore-ip-addresses/main.cpp
new file mode 100644
index 00000000..fa5a648b
--- /dev/null
+++ b/leetcode/cpp/0093.restore-ip-addresses/main.cpp
@@ -0,0 +1,78 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+
+#include
+#include
+#include
+
+class Solution {
+ public:
+ static bool isValidIpSector(const std::string& s) {
+ if (s.empty()) {
+ return false;
+ }
+ if (s.size() > 3) {
+ return false;
+ }
+ // Leading zero
+ if (s.size() > 1 && s[0] == '0') {
+ return false;
+ }
+ int val = std::stoi(s);
+ return val >=0 && val <= 255;
+ }
+
+ static
+ std::vector restoreIpAddresses(std::string s) {
+ std::vector out;
+ for (int i = 1; i <= 3 && i < s.size(); ++i) {
+ const std::string& first = s.substr(0, i);
+ if (!isValidIpSector(first)) {
+ continue;
+ }
+ for (int j = 1; j <= 3 && i + j < s.size(); ++j) {
+ const std::string& second = s.substr(i, j);
+ if (!isValidIpSector(second)) {
+ continue;
+ }
+
+ for (int k = 1; k <= 3 && i + j + k < s.size(); ++k) {
+ const std::string& third = s.substr(i + j, k);
+ const std::string& forth = s.substr(i + j + k);
+ if (isValidIpSector(third) && isValidIpSector(forth)) {
+ out.emplace_back(first + "." + second + "." + third + "." + forth);
+ }
+ }
+ }
+ }
+ return out;
+ }
+};
+
+void checkSolution(std::string s, std::vector exp_out) {
+ std::vector out = Solution::restoreIpAddresses(s);
+ printf("size: %d, exp: %d\n", out.size(), exp_out.size());
+ assert(out.size() == exp_out.size());
+ std::sort(out.begin(), out.end());
+ std::sort(exp_out.begin(), exp_out.end());
+ for (int i = 0; i < out.size(); ++i) {
+ assert(out[i] == exp_out[i]);
+ }
+}
+
+int main() {
+ checkSolution("25525511135", {"255.255.11.135", "255.255.111.35"});
+ checkSolution("101023", {
+ "1.0.10.23",
+ "1.0.102.3",
+ "10.1.0.23",
+ "10.10.2.3",
+ "101.0.2.3"
+ });
+
+ return 0;
+}
diff --git a/leetcode/cpp/0098.validate-binary-search-tree/CMakeLists.txt b/leetcode/cpp/0098.validate-binary-search-tree/CMakeLists.txt
new file mode 100644
index 00000000..d1c6de36
--- /dev/null
+++ b/leetcode/cpp/0098.validate-binary-search-tree/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0098-validate-binary-search-tree
+ main.c
+ )
diff --git a/leetcode/cpp/0098.validate-binary-search-tree/main.c b/leetcode/cpp/0098.validate-binary-search-tree/main.c
new file mode 100644
index 00000000..7253fb2d
--- /dev/null
+++ b/leetcode/cpp/0098.validate-binary-search-tree/main.c
@@ -0,0 +1,82 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+struct TreeNode* findMin(struct TreeNode* root) {
+ if (root == NULL) {
+ return NULL;
+ }
+ // traverse
+ struct TreeNode* left = findMin(root->left);
+ struct TreeNode* right = findMin(root->left);
+ struct TreeNode* min_node = root;
+ if (left != NULL && left->val < min_node->val) {
+ min_node = left;
+ }
+ if (right != NULL && right->val < min_node->val) {
+ min_node = right;
+ }
+ return min_node;
+}
+
+struct TreeNode* findMax(struct TreeNode* root) {
+ if (root == NULL) {
+ return NULL;
+ }
+ struct TreeNode* left = findMax(root->left);
+ struct TreeNode* right = findMax(root->left);
+ struct TreeNode* max_node = root;
+ if (left != NULL && left->val > max_node->val) {
+ max_node = left;
+ }
+ if (right != NULL && right->val > max_node->val) {
+ max_node = right;
+ }
+ return max_node;
+}
+
+bool isValidBST(struct TreeNode* root) {
+ if (root == NULL) {
+ return true;
+ }
+ struct TreeNode* left_max = findMax(root->left);
+ if (left_max != NULL && left_max->val >= root->val) {
+ return false;
+ }
+ struct TreeNode* right_min = findMin(root->right);
+ if (right_min != NULL && right_min->val <= root->val) {
+ return false;
+ }
+ return true;
+}
+
+bool isValidBST2Helper(struct TreeNode* root, long min, long max) {
+ if (root == NULL) {
+ return true;
+ }
+ if (root->val < max && root->val > min) {
+ return isValidBST2Helper(root->left, min, root->val) &&
+ isValidBST2Helper(root->right, root->val, max);
+ }
+ return false;
+}
+
+bool isValidBST2(struct TreeNode* root) {
+ return isValidBST2Helper(root, LONG_MIN, LONG_MAX);
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0101.symmetric-tree/CMakeLists.txt b/leetcode/cpp/0101.symmetric-tree/CMakeLists.txt
new file mode 100644
index 00000000..de99cb81
--- /dev/null
+++ b/leetcode/cpp/0101.symmetric-tree/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0101-symmetric-tree
+ main.c
+ )
diff --git a/leetcode/cpp/0101.symmetric-tree/main.c b/leetcode/cpp/0101.symmetric-tree/main.c
new file mode 100644
index 00000000..6aea52c1
--- /dev/null
+++ b/leetcode/cpp/0101.symmetric-tree/main.c
@@ -0,0 +1,36 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+bool isSymmetricHelper(struct TreeNode* left, struct TreeNode* right) {
+ if (left == NULL && right == NULL) {
+ return true;
+ }
+ if (left == NULL || right == NULL) {
+ return false;
+ }
+ if (left->val != right->val) {
+ return false;
+ }
+ return isSymmetricHelper(left->left, right->right) &&
+ isSymmetricHelper(left->right, right->left);
+}
+
+bool isSymmetric(struct TreeNode* root) {
+ return isSymmetricHelper(root->left, root->right);
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0102.binary-tree-level-order-traversal/CMakeLists.txt b/leetcode/cpp/0102.binary-tree-level-order-traversal/CMakeLists.txt
new file mode 100644
index 00000000..e7ae4972
--- /dev/null
+++ b/leetcode/cpp/0102.binary-tree-level-order-traversal/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0102-binary-tree-level-order-traversal
+ main.cpp
+ )
diff --git a/leetcode/cpp/0102.binary-tree-level-order-traversal/main.cpp b/leetcode/cpp/0102.binary-tree-level-order-traversal/main.cpp
new file mode 100644
index 00000000..95dc62e0
--- /dev/null
+++ b/leetcode/cpp/0102.binary-tree-level-order-traversal/main.cpp
@@ -0,0 +1,86 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+class Solution {
+ public:
+ void levelOrderHelper(std::queue queue, std::vector>& out) {
+ std::queue next_queue;
+ std::vector values;
+
+ while (!queue.empty()) {
+ TreeNode* node = queue.front();
+ queue.pop();
+ values.push_back(node->val);
+ if (node->left != nullptr) {
+ next_queue.push(node->left);
+ }
+ if (node->right != nullptr) {
+ next_queue.push(node->right);
+ }
+ }
+ out.push_back(values);
+
+ if (!next_queue.empty()) {
+ levelOrderHelper(next_queue, out);
+ }
+ }
+
+ std::vector> levelOrder(TreeNode* root) {
+ std::vector> out;
+ if (root == nullptr) {
+ return out;
+ }
+
+ std::queue queue;
+ queue.push(root);
+ levelOrderHelper(queue, out);
+
+ return out;
+ }
+
+ std::vector> levelOrderIterative(TreeNode* root) {
+ std::vector> out;
+ if (root == nullptr) {
+ return out;
+ }
+
+ std::queue queue;
+ queue.push(root);
+
+ while (!queue.empty()) {
+ size_t size = queue.size();
+ std::vector values;
+ // current level.
+ for (size_t i = 0; i < size; ++i) {
+ TreeNode* node = queue.front();
+ queue.pop();
+ values.push_back(node->val);
+ if (node->left != nullptr) {
+ queue.push(node->left);
+ }
+ if (node->right != nullptr) {
+ queue.push(node->right);
+ }
+ }
+ out.push_back(values);
+ }
+
+ return out;
+ }
+};
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/CMakeLists.txt b/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/CMakeLists.txt
new file mode 100644
index 00000000..664fb798
--- /dev/null
+++ b/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0103-binary-tree-zigzag-level-order-traversal
+ main.cpp
+ )
diff --git a/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/main.cpp b/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/main.cpp
new file mode 100644
index 00000000..b3cd6070
--- /dev/null
+++ b/leetcode/cpp/0103.binary-tree-zigzag-level-order-traversal/main.cpp
@@ -0,0 +1,56 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+class Solution {
+ public:
+ std::vector> zigzagLevelOrder(TreeNode* root) {
+ std::vector> out;
+ if (root == nullptr) {
+ return out;
+ }
+
+ std::queue queue;
+ queue.push(root);
+ bool do_reverse = false;
+
+ while (!queue.empty()) {
+ size_t size = queue.size();
+ std::vector values;
+ // current level.
+ for (size_t i = 0; i < size; ++i) {
+ TreeNode* node = queue.front();
+ queue.pop();
+ values.push_back(node->val);
+ if (node->left != nullptr) {
+ queue.push(node->left);
+ }
+ if (node->right != nullptr) {
+ queue.push(node->right);
+ }
+ }
+
+ if (do_reverse) {
+ std::reverse(values.begin(), values.end());
+ }
+ out.push_back(values);
+ do_reverse = !do_reverse;
+ }
+
+ return out;
+ }
+};
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/CMakeLists.txt b/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/CMakeLists.txt
new file mode 100644
index 00000000..c96235ac
--- /dev/null
+++ b/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0107-binary-tree-level-order-traversal-ii
+ main.cpp
+ )
diff --git a/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/main.cpp b/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/main.cpp
new file mode 100644
index 00000000..e7e76cbe
--- /dev/null
+++ b/leetcode/cpp/0107.binary-tree-level-order-traversal-ii/main.cpp
@@ -0,0 +1,51 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+class Solution {
+ public:
+ std::vector> levelOrderBottom(TreeNode* root) {
+ std::vector> out;
+ if (root == nullptr) {
+ return out;
+ }
+
+ std::queue queue;
+ queue.push(root);
+ while (!queue.empty()) {
+
+ // current level
+ size_t size = queue.size();
+ std::vector values;
+ for (size_t i = 0; i < size; ++i) {
+ TreeNode* node = queue.front();
+ queue.pop();
+ values.push_back(node->val);
+ if (node->left != nullptr) {
+ queue.push(node->left);
+ }
+ if (node->right != nullptr) {
+ queue.push(node->right);
+ }
+ }
+ out.push_back(values);
+ }
+
+ std::reverse(out.begin(), out.end());
+ return out;
+ }
+};
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/CMakeLists.txt b/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/CMakeLists.txt
new file mode 100644
index 00000000..1eedfb5c
--- /dev/null
+++ b/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0108-convert-sorted-array-to-binary-search-tree
+ main.c
+ )
diff --git a/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/main.c b/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/main.c
new file mode 100644
index 00000000..48f37e01
--- /dev/null
+++ b/leetcode/cpp/0108.convert-sorted-array-to-binary-search-tree/main.c
@@ -0,0 +1,18 @@
+
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+struct TreeNode* sortedArrayToBST(int* nums, int numsSize) {
+
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/CMakeLists.txt b/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/CMakeLists.txt
new file mode 100644
index 00000000..239d5bed
--- /dev/null
+++ b/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0114-flatten-binary-tree-to-linked-list
+ main.c
+ )
diff --git a/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/main.c b/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/main.c
new file mode 100644
index 00000000..1a40e101
--- /dev/null
+++ b/leetcode/cpp/0114.flatten-binary-tree-to-linked-list/main.c
@@ -0,0 +1,138 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+static struct TreeNode* treeNew(int val) {
+ struct TreeNode* node = malloc(sizeof(struct TreeNode));
+ assert(node != NULL);
+ node->val = val;
+ node->left = NULL;
+ node->right = NULL;
+ return node;
+}
+
+static struct TreeNode* treeFromArrayHelper(int arr[], int len, int index) {
+ if (index >= len) {
+ return NULL;
+ }
+
+ if (arr[index] == INT_MIN) {
+ return NULL;
+ }
+
+ struct TreeNode* node = treeNew(arr[index]);
+ node->left = treeFromArrayHelper(arr, len, index * 2 + 1);
+ node->right = treeFromArrayHelper(arr, len, index * 2 + 2);
+ return node;
+}
+
+static struct TreeNode* treeFromArray(int arr[], int len) {
+ assert(len >= 0);
+ struct TreeNode* root = treeFromArrayHelper(arr, len, 0);
+
+ return root;
+}
+
+static void treeFree(struct TreeNode* root) {
+ if (root != NULL) {
+ treeFree(root->left);
+ treeFree(root->right);
+ free(root);
+ }
+}
+
+static void treeTraversePreOrder(
+ struct TreeNode* node,
+ void (*apply)(struct TreeNode* node, void* user_data),
+ void* user_data) {
+ if (node != NULL) {
+ apply(node, user_data);
+ treeTraversePreOrder(node->left, apply, user_data);
+ treeTraversePreOrder(node->right, apply, user_data);
+ }
+}
+
+static void debugTreeNodeHelper(struct TreeNode* node) {
+ if (node != NULL) {
+ printf("%d, ", node->val);
+ debugTreeNodeHelper(node->left);
+ debugTreeNodeHelper(node->right);
+ } else {
+ printf("null, ");
+ }
+}
+
+static void debugTreeNode(struct TreeNode* root) {
+ assert(root != NULL);
+ debugTreeNodeHelper(root);
+ printf("\n");
+}
+
+static struct TreeNode* treeGetRightLeaf(struct TreeNode* root) {
+ if (root == NULL) {
+ return NULL;
+ }
+ while (root != NULL) {
+ if (root->right == NULL) {
+ return root;
+ }
+ root = root->right;
+ }
+ return NULL;
+}
+
+static void flatten(struct TreeNode* root) {
+ while (root != NULL) {
+ if (root->left != NULL) {
+ struct TreeNode* right_leaf = treeGetRightLeaf(root->left);
+ right_leaf->right = root->right;
+ root->right = root->left;
+ root->left = NULL;
+ }
+ root = root->right;
+ }
+}
+
+static void flatten2(struct TreeNode* root) {
+ while (root != NULL) {
+ if (root->left != NULL) {
+ struct TreeNode* right_leaf = root->left;
+ while (right_leaf->right != NULL) {
+ right_leaf = right_leaf->right;
+ }
+
+ right_leaf->right = root->right;
+ root->right = root->left;
+ root->left = NULL;
+ }
+ root = root->right;
+ }
+}
+
+static void checkSolution(int arr[], int len) {
+ struct TreeNode* root = treeFromArray(arr, len);
+ flatten(root);
+ //flatten2(root);
+ debugTreeNode(root);
+
+ treeFree(root);
+}
+
+int main() {
+ int arr[] = {1, 2, 5, 3, 4, INT_MIN, 6};
+ //int arr[] = {1, 2, INT_MIN, 3};
+ checkSolution(arr, sizeof(arr) / sizeof(arr[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0139.word-break/CMakeLists.txt b/leetcode/cpp/0139.word-break/CMakeLists.txt
new file mode 100644
index 00000000..307bf7e0
--- /dev/null
+++ b/leetcode/cpp/0139.word-break/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0139-word-break
+ main.cpp
+ )
diff --git a/leetcode/cpp/0139.word-break/main.cpp b/leetcode/cpp/0139.word-break/main.cpp
new file mode 100644
index 00000000..04ef8ca3
--- /dev/null
+++ b/leetcode/cpp/0139.word-break/main.cpp
@@ -0,0 +1,18 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+class Solution {
+ public:
+ static
+ bool wordBreak(std::string s, std::vector& wordDict) {
+ }
+};
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0141.linked-list-cycle/CMakeLists.txt b/leetcode/cpp/0141.linked-list-cycle/CMakeLists.txt
new file mode 100644
index 00000000..a69de6ce
--- /dev/null
+++ b/leetcode/cpp/0141.linked-list-cycle/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0141-linked-list-cycle
+ main.c
+ )
diff --git a/leetcode/cpp/0141.linked-list-cycle/main.c b/leetcode/cpp/0141.linked-list-cycle/main.c
new file mode 100644
index 00000000..995d4875
--- /dev/null
+++ b/leetcode/cpp/0141.linked-list-cycle/main.c
@@ -0,0 +1,119 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+struct ListNode* listConnectTailTo(struct ListNode* head, int pos) {
+ assert(head != NULL);
+ assert(pos > 0);
+
+ struct ListNode* curr = head;
+ struct ListNode* pos_node = NULL;
+ while (pos > 0) {
+ curr = curr->next;
+ pos -= 1;
+ }
+ assert(curr != NULL);
+ pos_node = curr;
+ while (curr->next != NULL) {
+ curr = curr->next;
+ }
+ curr->next = pos_node;
+
+ return head;
+}
+
+void listFree(struct ListNode* list) {
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+bool hasCycle(struct ListNode *head) {
+ struct ListNode* alert_node = listNew(INT_MIN);
+ struct ListNode* tmp = NULL;
+ while (head != NULL) {
+ if (head->next == alert_node) {
+ return true;
+ }
+ tmp = head;
+ head = head->next;
+ tmp->next = alert_node;
+ }
+ return false;
+}
+
+bool hasCycle2(struct ListNode *head) {
+ const int kResetVal = INT_MIN;
+ while (head != NULL) {
+ if (head->val == kResetVal) {
+ return true;
+ }
+ head->val = kResetVal;
+ head = head->next;
+ }
+ return false;
+}
+
+// Floyd’s Cycle-Finding Algorithm
+bool hasCycle3(struct ListNode *head) {
+ struct ListNode* fast = head;
+ struct ListNode* slow = head;
+
+ while (fast != NULL && fast->next != NULL) {
+ // 2 nodes forward
+ fast = fast->next->next;
+ // 1 node forward
+ slow = slow->next;
+
+ // Got the same node.
+ if (fast == slow) {
+ return true;
+ }
+ }
+ return false;
+}
+
+void checkSolution(int arr[], int len, int pos) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list2 = listConnectTailTo(list, pos);
+ bool ret = hasCycle(list2);
+ printf("has cycle: %d\n", ret);
+}
+
+int main() {
+ int arr[] = {3, 2, 0, -4};
+ checkSolution(arr, sizeof(arr) / sizeof(arr[0]), 1);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0142.linked-list-cycle-ii/CMakeLists.txt b/leetcode/cpp/0142.linked-list-cycle-ii/CMakeLists.txt
new file mode 100644
index 00000000..02026e98
--- /dev/null
+++ b/leetcode/cpp/0142.linked-list-cycle-ii/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0142-linked-list-cycle-ii
+ main.c
+ )
diff --git a/leetcode/cpp/0142.linked-list-cycle-ii/main.c b/leetcode/cpp/0142.linked-list-cycle-ii/main.c
new file mode 100644
index 00000000..f65b8b55
--- /dev/null
+++ b/leetcode/cpp/0142.linked-list-cycle-ii/main.c
@@ -0,0 +1,102 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+struct ListNode* listConnectTailTo(struct ListNode* head, int pos) {
+ assert(head != NULL);
+ assert(pos > 0);
+
+ struct ListNode* curr = head;
+ struct ListNode* pos_node = NULL;
+ while (pos > 0) {
+ curr = curr->next;
+ pos -= 1;
+ }
+ assert(curr != NULL);
+ pos_node = curr;
+ while (curr->next != NULL) {
+ curr = curr->next;
+ }
+ curr->next = pos_node;
+
+ return head;
+}
+
+void listFree(struct ListNode* list) {
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+// Floyd’s Cycle-Finding Algorithm
+struct ListNode* detectCycle(struct ListNode* head) {
+ struct ListNode* fast = head;
+ struct ListNode* slow = head;
+ while (fast != NULL && fast->next != NULL) {
+ // 2 nodes forward
+ fast = fast->next->next;
+ // 1 node forward
+ slow = slow->next;
+
+ if (fast == slow) {
+ // Found cycle.
+
+ // Reset slow to head of list.
+ slow = head;
+ while (slow != fast) {
+ // Wait until they meat again.
+ slow = slow->next;
+ fast = fast->next;
+ }
+ return slow;
+ }
+ }
+ return NULL;
+}
+
+void checkSolution(int arr[], int len, int pos) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list2 = listConnectTailTo(list, pos);
+ struct ListNode* cycle_list = detectCycle(list2);
+ while (cycle_list != NULL) {
+ printf("%d, ", cycle_list->val);
+ cycle_list = cycle_list->next;
+ }
+}
+
+int main() {
+ int arr[] = {3, 2, 0, -4};
+ checkSolution(arr, sizeof(arr) / sizeof(arr[0]), 1);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0144.binary-tree-preorder-traversal/CMakeLists.txt b/leetcode/cpp/0144.binary-tree-preorder-traversal/CMakeLists.txt
new file mode 100644
index 00000000..b6338df7
--- /dev/null
+++ b/leetcode/cpp/0144.binary-tree-preorder-traversal/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0144-binary-tree-preorder-traversal
+ main.cpp
+ )
diff --git a/leetcode/cpp/0144.binary-tree-preorder-traversal/main.cpp b/leetcode/cpp/0144.binary-tree-preorder-traversal/main.cpp
new file mode 100644
index 00000000..d61f99ff
--- /dev/null
+++ b/leetcode/cpp/0144.binary-tree-preorder-traversal/main.cpp
@@ -0,0 +1,36 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+
+struct TreeNode {
+ int val;
+ struct TreeNode* left;
+ struct TreeNode* right;
+};
+
+class Solution {
+public:
+ static
+ void helper(TreeNode* root, std::vector& values) {
+ if (root == nullptr) {
+ return;
+ }
+ values.push_back(root->val);
+ helper(root->left, values);
+ helper(root->right, values);
+ }
+
+ std::vector preorderTraversal(TreeNode* root) {
+ std::vector values;
+ helper(root, values);
+ return values;
+ }
+};
+
+
+int main() {
+
+ return 0;
+}
diff --git a/leetcode/cpp/0160.intersection-of-two-linked-lists/CMakeLists.txt b/leetcode/cpp/0160.intersection-of-two-linked-lists/CMakeLists.txt
new file mode 100644
index 00000000..3c0ecea7
--- /dev/null
+++ b/leetcode/cpp/0160.intersection-of-two-linked-lists/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0160-intersection-of-two-linked-lists
+ main.c
+ )
diff --git a/leetcode/cpp/0160.intersection-of-two-linked-lists/main.c b/leetcode/cpp/0160.intersection-of-two-linked-lists/main.c
new file mode 100644
index 00000000..85c41c46
--- /dev/null
+++ b/leetcode/cpp/0160.intersection-of-two-linked-lists/main.c
@@ -0,0 +1,53 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listSkip(struct ListNode* head, int count) {
+ while (count > 0) {
+ head = head->next;
+ assert(head != NULL);
+ count -= 1;
+ }
+ return head;
+}
+
+int listLen(struct ListNode* head) {
+ int count = 0;
+ while (head != NULL) {
+ head = head->next;
+ count += 1;
+ }
+ return count;
+}
+
+struct ListNode* getIntersectionNode(struct ListNode* headA, struct ListNode* headB) {
+ int len_a = listLen(headA);
+ int len_b = listLen(headB);
+ if (len_a > len_b) {
+ headA = listSkip(headA, len_a - len_b);
+ } else {
+ headB = listSkip(headB, len_b - len_a);
+ }
+
+ while (headA != NULL) {
+ if (headA == headB) {
+ return headA;
+ }
+ headA = headA->next;
+ headB = headB->next;
+ }
+ return NULL;
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0162.find-peak-element/CMakeLists.txt b/leetcode/cpp/0162.find-peak-element/CMakeLists.txt
new file mode 100644
index 00000000..91626075
--- /dev/null
+++ b/leetcode/cpp/0162.find-peak-element/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0162-find-peak-element
+ main.c
+ )
diff --git a/leetcode/cpp/0191.number-of-1-bits/CMakeLists.txt b/leetcode/cpp/0191.number-of-1-bits/CMakeLists.txt
new file mode 100644
index 00000000..6635c88b
--- /dev/null
+++ b/leetcode/cpp/0191.number-of-1-bits/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0191-number-of-1-bits
+ main.c
+ )
diff --git a/leetcode/cpp/0191.number-of-1-bits/main.c b/leetcode/cpp/0191.number-of-1-bits/main.c
new file mode 100644
index 00000000..a0684486
--- /dev/null
+++ b/leetcode/cpp/0191.number-of-1-bits/main.c
@@ -0,0 +1,18 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+
+int hammingWeight(uint32_t n) {
+ int count = 0;
+ while (n != 0) {
+ count += n % 2;
+ n /= 2;
+ }
+ return count;
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0199.binary-tree-right-side-view/CMakeLists.txt b/leetcode/cpp/0199.binary-tree-right-side-view/CMakeLists.txt
new file mode 100644
index 00000000..81c76663
--- /dev/null
+++ b/leetcode/cpp/0199.binary-tree-right-side-view/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0199-binary-tree-right-side-view
+ main.c
+ )
diff --git a/leetcode/cpp/0200.number-of-islands/CMakeLists.txt b/leetcode/cpp/0200.number-of-islands/CMakeLists.txt
new file mode 100644
index 00000000..ed4310b9
--- /dev/null
+++ b/leetcode/cpp/0200.number-of-islands/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0200-number-of-islands
+ main.c
+ )
diff --git a/leetcode/cpp/0203.remove-linked-list-elements/CMakeLists.txt b/leetcode/cpp/0203.remove-linked-list-elements/CMakeLists.txt
new file mode 100644
index 00000000..dd0bf066
--- /dev/null
+++ b/leetcode/cpp/0203.remove-linked-list-elements/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0203.remove-linked-list-elements
+ main.c
+ )
diff --git a/leetcode/cpp/0203.remove-linked-list-elements/main.c b/leetcode/cpp/0203.remove-linked-list-elements/main.c
new file mode 100644
index 00000000..801c5934
--- /dev/null
+++ b/leetcode/cpp/0203.remove-linked-list-elements/main.c
@@ -0,0 +1,113 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+void listFree(struct ListNode* list) {
+ while (list != NULL) {
+ struct ListNode* tmp = list;
+ list = list->next;
+ free(tmp);
+ }
+}
+
+struct ListNode* removeElements(struct ListNode* head, int val) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* curr = head;
+ struct ListNode* prev = NULL;
+
+ while (curr != NULL) {
+ if (curr->val == val) {
+ // Remove current node.
+ if (prev == NULL) {
+ assert(curr == head);
+ curr = curr->next;
+ free(head);
+ head = curr;
+ } else {
+ prev->next = curr->next;
+ free(curr);
+ curr = prev->next;
+ }
+ } else {
+ prev = curr;
+ curr = curr->next;
+ }
+ }
+ return head;
+}
+
+struct ListNode* removeElements2(struct ListNode* head, int val) {
+ if (head == NULL) {
+ return NULL;
+ }
+
+ struct ListNode* curr = head->next;
+ struct ListNode* prev = head;
+
+ while (curr != NULL) {
+ if (curr->val == val) {
+ // Remove current node.
+ prev->next = curr->next;
+ free(curr);
+ curr = prev->next;
+ } else {
+ prev = curr;
+ curr = curr->next;
+ }
+ }
+ if (head->val == val) {
+ curr = head;
+ head = head->next;
+ free(curr);
+ }
+ return head;
+}
+
+void checkSolution(int arr[], int len, int val) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* list2 = removeElements2(list, val);
+ list = list2;
+ while (list != NULL) {
+ printf("%d, ", list->val);
+ list = list->next;
+ }
+ printf("\n");
+ listFree(list2);
+}
+
+int main() {
+ int arr[] = {1,2,6,3,4,5,6};
+ checkSolution(arr, sizeof(arr) / sizeof(arr[0]), 6);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0206.reverse-linked-list/CMakeLists.txt b/leetcode/cpp/0206.reverse-linked-list/CMakeLists.txt
new file mode 100644
index 00000000..6affc6ab
--- /dev/null
+++ b/leetcode/cpp/0206.reverse-linked-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0206-reverse-linked-list
+ main.c
+ )
diff --git a/leetcode/cpp/0206.reverse-linked-list/main.c b/leetcode/cpp/0206.reverse-linked-list/main.c
new file mode 100644
index 00000000..52142915
--- /dev/null
+++ b/leetcode/cpp/0206.reverse-linked-list/main.c
@@ -0,0 +1,79 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+void listFree(struct ListNode* head) {
+ while (head != NULL) {
+ struct ListNode* tmp = head;
+ head = head->next;
+ free(tmp);
+ }
+}
+
+void listDebug(struct ListNode* head) {
+ while (head != NULL) {
+ printf("%d, ", head->val);
+ head = head->next;
+ }
+ printf("\n");
+}
+
+struct ListNode* reverseList(struct ListNode* head) {
+ if (head == NULL) {
+ return NULL;
+ }
+ struct ListNode* prev = NULL;
+ struct ListNode* next = NULL;
+ while (head != NULL) {
+ next = head->next;
+ head->next = prev;
+ prev = head;
+ head = next;
+ }
+ return prev;
+}
+
+void checkSolution(int arr[], int len) {
+ struct ListNode* list = listFromArray(arr, len);
+ listDebug(list);
+ list = reverseList(list);
+ listDebug(list);
+ listFree(list);
+}
+
+int main() {
+ int arr1[] = {1, 2, 3, 4, 5};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ int arr2[] = {1, 2};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0215.kth-largest-element-in-an-array/CMakeLists.txt b/leetcode/cpp/0215.kth-largest-element-in-an-array/CMakeLists.txt
new file mode 100644
index 00000000..9c0331b4
--- /dev/null
+++ b/leetcode/cpp/0215.kth-largest-element-in-an-array/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0215-kth-largest-element-in-an-array
+ main.c
+ )
diff --git a/leetcode/cpp/0234.palindrome-linked-list/CMakeLists.txt b/leetcode/cpp/0234.palindrome-linked-list/CMakeLists.txt
new file mode 100644
index 00000000..e71ef6a2
--- /dev/null
+++ b/leetcode/cpp/0234.palindrome-linked-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0234-palindrome-linked-list
+ main.c
+ )
diff --git a/leetcode/cpp/0234.palindrome-linked-list/main.c b/leetcode/cpp/0234.palindrome-linked-list/main.c
new file mode 100644
index 00000000..5de03065
--- /dev/null
+++ b/leetcode/cpp/0234.palindrome-linked-list/main.c
@@ -0,0 +1,102 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+void listFree(struct ListNode* head) {
+ while (head != NULL) {
+ struct ListNode* node = head;
+ head = head->next;
+ free(node);
+ }
+}
+
+void listDebug(struct ListNode* head) {
+ while (head != NULL) {
+ printf("%d, ", head->val);
+ head = head->next;
+ }
+ printf("\n");
+}
+
+bool isPalindrome(struct ListNode* head) {
+ if (head == NULL) {
+ return true;
+ }
+
+ // 1. Reverse left half of list.
+ struct ListNode* slow = head;
+ struct ListNode* fast = head;
+ struct ListNode* next = NULL;
+ struct ListNode* prev = NULL;
+
+ while (fast != NULL && fast->next != NULL) {
+ slow = slow->next;
+ fast = fast->next->next;
+
+ // Reverse via slow node.
+ next = head->next;
+ head->next = prev;
+ prev = head;
+ head = next;
+ }
+
+ if (fast != NULL) {
+ slow = slow->next;
+ }
+ head = prev;
+
+ // 2. Compare from middle.
+ while (slow != NULL) {
+ if (slow->val != head->val) {
+ return false;
+ }
+ head = head->next;
+ slow = slow->next;
+ }
+ return true;
+}
+
+void checkSolution(int arr[], int len) {
+ struct ListNode* list = listFromArray(arr, len);
+ listDebug(list);
+ printf("is palindrome: %d\n", isPalindrome(list));
+ listFree(list);
+}
+
+int main() {
+ int arr1[] = {1, 2, 2, 1};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ int arr2[] = {1, 2,};
+ checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+
+ return 0;
+}
diff --git a/leetcode/cpp/0237.delete-node-in-a-linked-list/CMakeLists.txt b/leetcode/cpp/0237.delete-node-in-a-linked-list/CMakeLists.txt
new file mode 100644
index 00000000..fe37c2d4
--- /dev/null
+++ b/leetcode/cpp/0237.delete-node-in-a-linked-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0237-delete-node-in-a-linked-list
+ main.c
+ )
diff --git a/leetcode/cpp/0237.delete-node-in-a-linked-list/main.c b/leetcode/cpp/0237.delete-node-in-a-linked-list/main.c
new file mode 100644
index 00000000..717a0895
--- /dev/null
+++ b/leetcode/cpp/0237.delete-node-in-a-linked-list/main.c
@@ -0,0 +1,73 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+void listFree(struct ListNode* head) {
+ while (head != NULL) {
+ struct ListNode* node = head;
+ head = head->next;
+ free(node);
+ }
+}
+
+void listDebug(struct ListNode* head) {
+ while (head != NULL) {
+ printf("%d, ", head->val);
+ head = head->next;
+ }
+ printf("\n");
+}
+
+void deleteNode(struct ListNode* node) {
+ assert(node != NULL);
+ assert(node->next != NULL);
+ struct ListNode* tmp = node->next;
+ node->val = tmp->val;
+ node->next = tmp->next;
+ free(tmp);
+}
+
+void checkSolution(int arr[], int len, int target) {
+ struct ListNode* list = listFromArray(arr, len);
+ struct ListNode* node = list;
+ for (int i = 0; i < target; ++i) {
+ node = node->next;
+ }
+ deleteNode(node);
+ listDebug(list);
+ listFree(list);
+}
+
+int main() {
+ int arr[] = {4, 5, 1, 9};
+ checkSolution(arr, sizeof(arr) / sizeof(arr[0]), 2);
+
+ return 0;
+}
diff --git a/leetcode/cpp/0308.odd-even-linked-list/CMakeLists.txt b/leetcode/cpp/0308.odd-even-linked-list/CMakeLists.txt
new file mode 100644
index 00000000..58a7a525
--- /dev/null
+++ b/leetcode/cpp/0308.odd-even-linked-list/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0308-odd-even-linked-list
+ main.c
+ )
diff --git a/leetcode/cpp/0308.odd-even-linked-list/main.c b/leetcode/cpp/0308.odd-even-linked-list/main.c
new file mode 100644
index 00000000..b72e6098
--- /dev/null
+++ b/leetcode/cpp/0308.odd-even-linked-list/main.c
@@ -0,0 +1,92 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode* next;
+};
+
+struct ListNode* listNew(int val) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = val;
+ node->next = NULL;
+ return node;
+}
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = listNew(arr[i]);
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+void listFree(struct ListNode* head) {
+ while (head != NULL) {
+ struct ListNode* tmp = head;
+ head = head->next;
+ free(tmp);
+ }
+}
+
+void listDebug(struct ListNode* head) {
+ while (head != NULL) {
+ printf("%d, ", head->val);
+ head = head->next;
+ }
+ printf("\n");
+}
+
+struct ListNode* oddEvenList(struct ListNode* head) {
+ if (head == NULL || head->next == NULL) {
+ return NULL;
+ }
+ struct ListNode* even_head = head->next;
+ struct ListNode* even = head->next;
+ struct ListNode* odd = head;
+ struct ListNode* old_next = NULL;
+
+ while (odd != NULL && odd->next != NULL) {
+ printf("odd: %d\n", odd->val);
+ old_next = odd->next;
+ odd->next = old_next->next;
+ odd = old_next->next;
+ }
+
+ /*
+ while (even != NULL && even->next != NULL) {
+ old_next = even->next;
+ even->next = old_next->next;
+ }
+ */
+
+ assert(odd != NULL);
+ //odd->next = even_head;
+ //even->next = NULL;
+ return head;
+}
+
+void checkSolution(int arr[], int len) {
+ struct ListNode* list = listFromArray(arr, len);
+ listDebug(list);
+ list = oddEvenList(list);
+ listDebug(list);
+ listFree(list);
+}
+
+int main() {
+ int arr1[] = {1, 2, 3, 4, 5, 6, 7};
+ checkSolution(arr1, sizeof(arr1) / sizeof(arr1[0]));
+
+ //int arr2[] = {2, 1, 3, 5, 6, 4, 7};
+ //checkSolution(arr2, sizeof(arr2) / sizeof(arr2[0]));
+ return 0;
+}
diff --git a/leetcode/cpp/0443.string-compression/CMakeLists.txt b/leetcode/cpp/0443.string-compression/CMakeLists.txt
new file mode 100644
index 00000000..86e586b6
--- /dev/null
+++ b/leetcode/cpp/0443.string-compression/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0443-string-compression
+ main.c
+ )
diff --git a/leetcode/cpp/0445.add-two-numbers-ii/CMakeLists.txt b/leetcode/cpp/0445.add-two-numbers-ii/CMakeLists.txt
new file mode 100644
index 00000000..19d85a1c
--- /dev/null
+++ b/leetcode/cpp/0445.add-two-numbers-ii/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0445-add-two-numbers-ii
+ main.c
+ )
diff --git a/leetcode/cpp/0445.add-two-numbers-ii/main.c b/leetcode/cpp/0445.add-two-numbers-ii/main.c
new file mode 100644
index 00000000..bc0c7913
--- /dev/null
+++ b/leetcode/cpp/0445.add-two-numbers-ii/main.c
@@ -0,0 +1,89 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+#include
+#include
+#include
+
+struct ListNode {
+ int val;
+ struct ListNode *next;
+};
+
+struct ListNode* listFromArray(int arr[], int len) {
+ struct ListNode* list = NULL;
+ for (int i = len - 1; i >= 0; --i) {
+ struct ListNode* node = malloc(sizeof(struct ListNode));
+ assert(node != NULL);
+ node->val = arr[i];
+ node->next = list;
+ list = node;
+ }
+ return list;
+}
+
+static
+struct ListNode* listReverse(struct ListNode* list) {
+ struct ListNode* previous = NULL;
+ struct ListNode* next = NULL;
+
+ while (list != NULL) {
+ next = list->next;
+ list->next = previous;
+ previous = list;
+ list = next;
+ }
+ return previous;
+}
+
+struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
+ assert(l1 != NULL);
+ assert(l2 != NULL);
+ l1 = listReverse(l1);
+ l2 = listReverse(l2);
+
+ struct ListNode* l3 = NULL;
+ struct ListNode* tail_node = NULL;
+ int carry = 0;
+
+ while (l1 != NULL || l2 != NULL || carry != 0) {
+ int sum = carry;
+ if (l1 != NULL) {
+ sum += l1->val;
+ l1 = l1->next;
+ }
+ if (l2 != NULL) {
+ sum += l2->val;
+ l2 = l2->next;
+ }
+ carry = sum / 10;
+ struct ListNode* new_node = malloc(sizeof(struct ListNode));
+ assert(new_node != NULL);
+ new_node->val = sum % 10;
+ new_node->next = NULL;
+ if (tail_node == NULL) {
+ l3 = new_node;
+ tail_node = new_node;
+ } else {
+ tail_node->next = new_node;
+ tail_node = new_node;
+ }
+ }
+ return listReverse(l3);
+}
+
+int main() {
+ int arr1[] = {7, 2, 4, 3};
+ int arr2[] = {5, 6, 4};
+ struct ListNode* l1 = listFromArray(arr1, 4);
+ struct ListNode* l2 = listFromArray(arr2, 3);
+ struct ListNode* l3 = addTwoNumbers(l1, l2);
+ while (l3 != NULL) {
+ printf("%d, ", l3->val);
+ l3 = l3->next;
+ }
+ printf("\n");
+
+ return 0;
+}
diff --git a/leetcode/cpp/0695.max-area-of-island/CMakeLists.txt b/leetcode/cpp/0695.max-area-of-island/CMakeLists.txt
new file mode 100644
index 00000000..6d9ebb08
--- /dev/null
+++ b/leetcode/cpp/0695.max-area-of-island/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0695-max-area-of-island
+ main.c
+ )
diff --git a/leetcode/cpp/0704.binary-search/CMakeLists.txt b/leetcode/cpp/0704.binary-search/CMakeLists.txt
new file mode 100644
index 00000000..e674b68a
--- /dev/null
+++ b/leetcode/cpp/0704.binary-search/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0704-binary-search
+ main.c
+ )
diff --git a/leetcode/cpp/0704.binary-search/main.c b/leetcode/cpp/0704.binary-search/main.c
new file mode 100644
index 00000000..921b41c4
--- /dev/null
+++ b/leetcode/cpp/0704.binary-search/main.c
@@ -0,0 +1,30 @@
+// Copyright (c) 2024 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+int search(int* nums, int numsSize, int target) {
+ if (numsSize == 0) {
+ return -1;
+ }
+
+ int left = 0;
+ int right = numsSize - 1;
+ int middle;
+
+ while (left <= right) {
+ middle = left + (right - left) / 2;
+ if (nums[middle] == target) {
+ return middle;
+ }
+ if (nums[middle] > target) {
+ right = middle - 1;
+ } else {
+ left = middle + 1;
+ }
+ }
+ return -1;
+}
+
+int main() {
+ return 0;
+}
diff --git a/leetcode/cpp/0994.rotting-oranges/CMakeLists.txt b/leetcode/cpp/0994.rotting-oranges/CMakeLists.txt
new file mode 100644
index 00000000..e091f9f6
--- /dev/null
+++ b/leetcode/cpp/0994.rotting-oranges/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-0994-rotting-oranges
+ main.c
+ )
diff --git a/leetcode/cpp/1090.largest-values-from-labels/CMakeLists.txt b/leetcode/cpp/1090.largest-values-from-labels/CMakeLists.txt
new file mode 100644
index 00000000..5e43dc78
--- /dev/null
+++ b/leetcode/cpp/1090.largest-values-from-labels/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-1090-largest-values-from-labels
+ main.c
+ )
diff --git a/leetcode/cpp/1090.largest-values-from-labels/main.c b/leetcode/cpp/1090.largest-values-from-labels/main.c
new file mode 100644
index 00000000..e69de29b
diff --git a/leetcode/cpp/1423.maximum-points-you-can-obtain-from-cards/CMakeLists.txt b/leetcode/cpp/1423.maximum-points-you-can-obtain-from-cards/CMakeLists.txt
new file mode 100644
index 00000000..b344be06
--- /dev/null
+++ b/leetcode/cpp/1423.maximum-points-you-can-obtain-from-cards/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_executable(lc-1423-maximum-points-you-can-obtain-from-cards
+ main.c
+ )
diff --git a/leetcode/cpp/1423.maximum-points-you-can-obtain-from-cards/main.c b/leetcode/cpp/1423.maximum-points-you-can-obtain-from-cards/main.c
new file mode 100644
index 00000000..e69de29b
diff --git a/leetcode/cpp/CMakeLists.txt b/leetcode/cpp/CMakeLists.txt
new file mode 100644
index 00000000..6173afba
--- /dev/null
+++ b/leetcode/cpp/CMakeLists.txt
@@ -0,0 +1,63 @@
+
+cmake_minimum_required(VERSION 3.10)
+project(leetcode-cpp)
+
+add_subdirectory(0002.add-two-numbers)
+add_subdirectory(0003.longest-substring-without-repeating-characters)
+add_subdirectory(0005.longest-palindromic-substring)
+add_subdirectory(0007.reverse-integer)
+add_subdirectory(0008.string-to-integer-atoi)
+add_subdirectory(0011.container-with-most-water)
+add_subdirectory(0014.longest-common-prefix)
+add_subdirectory(0015.3sum)
+add_subdirectory(0016.3sum-closest)
+add_subdirectory(0018.4sum)
+add_subdirectory(0019.remove-nth-node-from-end-of-list)
+add_subdirectory(0020.valid-parentheses)
+add_subdirectory(0021.merge-two-sorted-lists)
+#add_subdirectory(0025.reverse-nodes-in-k-group)
+add_subdirectory(0026.remove-duplicates-from-sorted-array)
+add_subdirectory(0027.remove-element)
+#add_subdirectory(0031.next-permutation)
+add_subdirectory(0034.find-first-and-last-position-of-element-in-sorted-array)
+#add_subdirectory(0035.search-insert-position)
+#add_subdirectory(0053.maximum-subarray)
+add_subdirectory(0061.rotate-list)
+#add_subdirectory(0062.unique-paths)
+add_subdirectory(0066.plus-one)
+add_subdirectory(0070.climbing-stairs)
+add_subdirectory(0082.remove-duplicates-from-sorted-list-ii)
+add_subdirectory(0083.remove-duplicates-from-sorted-list)
+add_subdirectory(0086.partition-list)
+add_subdirectory(0088.merge-sorted-array)
+add_subdirectory(0092.reverse-linked-list-ii)
+add_subdirectory(0093.restore-ip-addresses)
+add_subdirectory(0098.validate-binary-search-tree)
+add_subdirectory(0101.symmetric-tree)
+add_subdirectory(0102.binary-tree-level-order-traversal)
+add_subdirectory(0103.binary-tree-zigzag-level-order-traversal)
+add_subdirectory(0107.binary-tree-level-order-traversal-ii)
+add_subdirectory(0108.convert-sorted-array-to-binary-search-tree)
+add_subdirectory(0114.flatten-binary-tree-to-linked-list)
+add_subdirectory(0139.word-break)
+add_subdirectory(0141.linked-list-cycle)
+add_subdirectory(0142.linked-list-cycle-ii)
+add_subdirectory(0144.binary-tree-preorder-traversal)
+add_subdirectory(0160.intersection-of-two-linked-lists)
+#add_subdirectory(0162.find-peak-element)
+add_subdirectory(0191.number-of-1-bits)
+#add_subdirectory(0199.binary-tree-right-side-view)
+#add_subdirectory(0200.number-of-islands)
+add_subdirectory(0203.remove-linked-list-elements)
+add_subdirectory(0206.reverse-linked-list)
+#add_subdirectory(0215.kth-largest-element-in-an-array)
+add_subdirectory(0234.palindrome-linked-list)
+add_subdirectory(0237.delete-node-in-a-linked-list)
+add_subdirectory(0308.odd-even-linked-list)
+#add_subdirectory(0443.string-compression)
+add_subdirectory(0445.add-two-numbers-ii)
+#add_subdirectory(0695.max-area-of-island)
+add_subdirectory(0704.binary-search)
+#add_subdirectory(0994.rotting-oranges)
+#add_subdirectory(1090.largest-values-from-labels)
+#add_subdirectory(1423.maximum-points-you-can-obtain-from-cards)
diff --git a/leetcode/rust/0001.two-sum/Cargo.toml b/leetcode/rust/0001.two-sum/Cargo.toml
new file mode 100644
index 00000000..9571a5d2
--- /dev/null
+++ b/leetcode/rust/0001.two-sum/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "lc-0001-two-sum"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
diff --git a/leetcode/rust/0001.two-sum/src/main.rs b/leetcode/rust/0001.two-sum/src/main.rs
new file mode 100644
index 00000000..7aae6857
--- /dev/null
+++ b/leetcode/rust/0001.two-sum/src/main.rs
@@ -0,0 +1,86 @@
+// Copyright (c) 2023 Xu Shaohua . All rights reserved.
+// Use of this source is governed by General Public License that can be
+// found in the LICENSE file.
+
+use std::collections::HashMap;
+
+fn solution1(nums: Vec, target: i32) -> Vec {
+ let mut result = Vec::new();
+ for (i, m) in nums.iter().enumerate() {
+ for (j, n) in nums.iter().enumerate() {
+ if i != j && m + n == target {
+ result.push(i as i32);
+ result.push(j as i32);
+ return result;
+ }
+ }
+ }
+ result
+}
+
+fn solution2(nums: Vec, target: i32) -> Vec {
+ let len = nums.len();
+ for i in 0..(len - 1) {
+ for j in (i + 1)..len {
+ if i != j && nums[i] + nums[j] == target {
+ return vec![i as i32, j as i32];
+ }
+ }
+ }
+ Vec::new()
+}
+
+fn solution3(nums: Vec, target: i32) -> Vec