From 667629ee916acc049885d2620965dc9e6df7f006 Mon Sep 17 00:00:00 2001
From: Spxg <unsafe@outlook.es>
Date: Tue, 14 May 2024 14:19:52 +0800
Subject: [PATCH] Add problem 0029: Divide Two Integers

---
 src/lib.rs                                    |  1 +
 .../bit_manipulation.rs                       | 57 +++++++++++++++++++
 src/problem_0029_divide_two_integers/mod.rs   | 28 +++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 src/problem_0029_divide_two_integers/bit_manipulation.rs
 create mode 100644 src/problem_0029_divide_two_integers/mod.rs

diff --git a/src/lib.rs b/src/lib.rs
index 82d667b..8adea0d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -146,6 +146,7 @@ pub mod problem_0024_swap_nodes_in_pairs;
 pub mod problem_0026_remove_duplicates_from_sorted_array;
 pub mod problem_0027_remove_element;
 pub mod problem_0028_find_the_index_of_the_first_occurrence_in_a_string;
+pub mod problem_0029_divide_two_integers;
 pub mod problem_0031_next_permutation;
 pub mod problem_0033_search_in_rotated_sorted_array;
 pub mod problem_0034_find_first_and_last_position_of_element_in_sorted_array;
diff --git a/src/problem_0029_divide_two_integers/bit_manipulation.rs b/src/problem_0029_divide_two_integers/bit_manipulation.rs
new file mode 100644
index 0000000..8185726
--- /dev/null
+++ b/src/problem_0029_divide_two_integers/bit_manipulation.rs
@@ -0,0 +1,57 @@
+pub struct Solution;
+
+impl Solution {
+    pub fn divide(dividend: i32, divisor: i32) -> i32 {
+        let negative = (dividend < 0) ^ (divisor < 0);
+        let mut dividend = if dividend == i32::MIN {
+            u32::from_le_bytes(dividend.to_le_bytes())
+        } else {
+            dividend.unsigned_abs()
+        };
+        let mut divisor = divisor.unsigned_abs();
+        let max_offset = divisor.leading_zeros();
+        let bound = u32::from_le_bytes(i32::MIN.to_le_bytes());
+
+        let mut result = 0;
+        let mut count = 0;
+
+        while dividend >= (divisor << 1) && count < max_offset {
+            count += 1;
+            divisor <<= 1;
+        }
+
+        for offset in (0..=count).rev() {
+            if dividend >= divisor {
+                result += 1 << offset;
+                dividend -= divisor;
+            }
+            divisor >>= 1;
+        }
+
+        if result >= bound {
+            if negative {
+                i32::MIN
+            } else {
+                i32::MAX
+            }
+        } else if negative {
+            -(result as i32)
+        } else {
+            result as i32
+        }
+    }
+}
+
+impl super::Solution for Solution {
+    fn divide(dividend: i32, divisor: i32) -> i32 {
+        Self::divide(dividend, divisor)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}
diff --git a/src/problem_0029_divide_two_integers/mod.rs b/src/problem_0029_divide_two_integers/mod.rs
new file mode 100644
index 0000000..135f955
--- /dev/null
+++ b/src/problem_0029_divide_two_integers/mod.rs
@@ -0,0 +1,28 @@
+pub mod bit_manipulation;
+
+pub trait Solution {
+    fn divide(dividend: i32, divisor: i32) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ((10, 3), 3),
+            ((7, -3), -2),
+            ((0, 1), 0),
+            ((1, 1), 1),
+            ((1_100_540_749, -1_090_366_779), -1),
+            ((2_147_483_647, 1), 2_147_483_647),
+            ((-2_147_483_648, -1), 2_147_483_647),
+            ((-10, 3), -3),
+            ((-7, -3), 2),
+        ];
+
+        for ((dividend, divisor), expected) in test_cases {
+            assert_eq!(S::divide(dividend, divisor), expected);
+        }
+    }
+}