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Tzu Hsiang Lin
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,139 @@ | ||
| ''' | ||
| 1247. Minimum Swaps to Make Strings Equal | ||
| https://leetcode.com/contest/weekly-contest-161/problems/minimum-swaps-to-make-strings-equal/ | ||
| You are given two strings s1 and s2 of equal length | ||
| consisting of letters "x" and "y" only. | ||
| Your task is to make these two strings equal to each other. | ||
| You can swap any two characters that belong to different strings, | ||
| which means: swap s1[i] and s2[j]. | ||
| Return the minimum number of swaps required to make s1 and s2 equal, | ||
| or return -1 if it is impossible to do so. | ||
| Example 1: | ||
| Input: s1 = "xx", s2 = "yy" | ||
| Output: 1 | ||
| Explanation: | ||
| Swap s1[0] and s2[1], s1 = "yx", s2 = "yx". | ||
| Example 2: | ||
| Input: s1 = "xy", s2 = "yx" | ||
| Output: 2 | ||
| Explanation: | ||
| Swap s1[0] and s2[0], s1 = "yy", s2 = "xx". | ||
| Swap s1[0] and s2[1], s1 = "xy", s2 = "xy". | ||
| Note that you can't swap s1[0] and s1[1] to make s1 equal to "yx", | ||
| cause we can only swap chars in different strings. | ||
| Example 3: | ||
| Input: s1 = "xx", s2 = "xy" | ||
| Output: -1 | ||
| Example 4: | ||
| Input: s1 = "xxyyxyxyxx", s2 = "xyyxyxxxyx" | ||
| Output: 4 | ||
| Constraints: | ||
| 1 <= s1.length, s2.length <= 1000 | ||
| s1, s2 only contain 'x' or 'y'. | ||
| ''' | ||
| from typing import * | ||
|
|
||
| class Solution: | ||
| def minimumSwap(self, s1: str, s2: str) -> int: | ||
| xy, yx = 0, 0 | ||
|
|
||
| for c1, c2 in zip(s1, s2): | ||
| if c1=='x' and c2=='y': | ||
| xy += 1 | ||
| elif c1=='y' and c2=='x': | ||
| yx += 1 | ||
|
|
||
| # if number of 'x' or 'y' is odd, we can not make s1 equals to s2 | ||
| if (xy + yx) % 2 != 0: | ||
| return -1 | ||
|
|
||
| # Cases to do 1 swap: | ||
| # "xx" => xy // 2 => how many pairs of 'x' we have ? | ||
| # "yy" => yx // 2 => how many pairs of 'y' we have ? | ||
| # | ||
| # Cases to do 2 swaps: | ||
| # "xy" or "yx" => xy % 2 | ||
| return xy // 2 + yx // 2 + (xy % 2) * 2 | ||
|
|
||
| import unittest | ||
|
|
||
| class MinSwapTest(unittest.TestCase): | ||
|
|
||
| def testCase1Swap(self): | ||
| self.assertEqual(Solution().minimumSwap(s1 = "xx", s2 = "yy"), 1) | ||
| # s1=xx | ||
| # s2=yy | ||
| # ↓↓ 0↑(yx) 2↓(xy) | ||
| #1 | ||
| self.assertEqual(Solution().minimumSwap(s1="yy", s2="xx"), 1) | ||
| # s1=yy | ||
| # s2=xx | ||
| # ↑↑ 2↑(yx) 0↓(xy) | ||
| #1 | ||
| self.assertEqual(Solution().minimumSwap(s1="xxxx", s2="yyyy"), 2) | ||
| # s1=xxxx | ||
| # s2=yyyy | ||
| # ↓↓↓↓ 0↑(yx) 4↓(xy) | ||
| # 2 | ||
|
|
||
| def testCase2Swap(self): | ||
| self.assertEqual(Solution().minimumSwap(s1 = "xy", s2 = "yx"), 2) | ||
| # s1=xy | ||
| # s2=yx | ||
| # ↓↑ 1↑(yx) 1↓(xy) | ||
| #2 | ||
|
|
||
| def testMixedCase(self): | ||
| self.assertEqual(Solution().minimumSwap(s1 = "xyxx", s2 = "yxyy"), 3) | ||
| # s1=xyxx | ||
| # s2=yxyy | ||
| # ↓↑↓↓ 1↑(yx) 3↓(xy) | ||
| #3 | ||
| self.assertEqual(Solution().minimumSwap(s1 = "xxyxy", s2 = "yyyyx"), 3) | ||
| # s1=xxyxy | ||
| # s2=yyyyx | ||
| # ↓↓ ↓↑ 1↑(yx) 3↓(xy) | ||
| # 3 | ||
| self.assertEqual(Solution().minimumSwap(s1="xxyyxyxyxx", s2="xyyxyxxxyx"), 4) | ||
| # s1=xxyyxyxyxx | ||
| # s2=xyyxyxxxyx | ||
| # ↓ ↑↓↑ ↑↓ 3↑(yx) 3↓(xy) | ||
| # 4 | ||
|
|
||
| def testInvalidCase(self): | ||
| self.assertEqual(Solution().minimumSwap(s1="xx", s2="xy"), -1) | ||
| # s1=xx | ||
| # s2=xy | ||
| # ↓ 0↑(yx) 1↓(xy) | ||
| #-1 | ||
| self.assertEqual(Solution().minimumSwap(s1 = "xyxx", s2 = "yyyy"), -1) | ||
| # s1=xyxx | ||
| # s2=yyyy | ||
| # ↓ ↓↓ 0↑(yx) 3↓(xy) | ||
| #-1 | ||
|
|
||
| if __name__ == "__main__": | ||
| unittest.main() | ||
|
|
||
| #2,2,2,1,2,2,1 | ||
| #2,2,2,1,2,2,1,2 | ||
| #2,2,2,1,2,2,1,2,2 | ||
| #2,2,2,1,2,2,1,2,2,2 | ||
| # 2,2,1,2,2,1,2,2,2 | ||
| # 2,1,2,2,1,2,2,2 | ||
| # 1,2,2,1,2,2,2 | ||
| # 1,2,2,1,2,2 | ||
| # 1,2,2,1,2 | ||
| # 1,2,2,1 | ||
| # 2,1,2,2,1 | ||
| # 2,1,2,2,1,2 | ||
| # 2,1,2,2,1,2,2 | ||
| # 2,2,1,2,2,1 | ||
| # 2,2,1,2,2,1,2 | ||
| # 2,2,1,2,2,1,2,2 |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,64 @@ | ||
| ''' | ||
| 1248. Count Number of Nice Subarrays | ||
| https://leetcode.com/problems/count-number-of-nice-subarrays/ | ||
| Given an array of integers nums and an integer k. | ||
| A subarray is called nice if there are k odd numbers on it. | ||
| Return the number of nice sub-arrays. | ||
| Example 1: | ||
| Input: nums = [1,1,2,1,1], k = 3 | ||
| Output: 2 | ||
| Explanation: | ||
| The only sub-arrays with 3 odd numbers are [1,1,2,1] and [1,2,1,1]. | ||
| Example 2: | ||
| Input: nums = [2,4,6], k = 1 | ||
| Output: 0 | ||
| Explanation: There is no odd numbers in the array. | ||
| Example 3: | ||
| Input: nums = [2,2,2,1,2,2,1,2,2,2], k = 2 | ||
| Output: 16 | ||
| Constraints: | ||
| 1 <= nums.length <= 50000 | ||
| 1 <= nums[i] <= 10^5 | ||
| 1 <= k <= nums.length | ||
| ''' | ||
| from typing import * | ||
|
|
||
| class Solution: | ||
| def numberOfSubarrays(self, nums: List[int], k: int) -> int: | ||
| def atMost(numOdd): | ||
| numSubArr = left = 0 | ||
| for idx in range(len(nums)): | ||
| numOdd -= nums[idx] % 2 | ||
| while numOdd < 0: | ||
| numOdd += nums[left] % 2 | ||
| left += 1 | ||
| numSubArr += idx - left + 1 | ||
| return numSubArr | ||
|
|
||
| return atMost(k) - atMost(k - 1) | ||
|
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||
| #print(Solution().numberOfSubarrays(nums = [1,1,2,1,1], k = 3)) | ||
| #2 | ||
| print(Solution().numberOfSubarrays(nums = [2,2,2,1,2,2,1,2,2,2], k = 2)) | ||
| #16 | ||
| #2,2,2,1,2,2,1 | ||
| #2,2,2,1,2,2,1,2 | ||
| #2,2,2,1,2,2,1,2,2 | ||
| #2,2,2,1,2,2,1,2,2,2 | ||
| # 2,2,1,2,2,1,2,2,2 | ||
| # 2,1,2,2,1,2,2,2 | ||
| # 1,2,2,1,2,2,2 | ||
| # 1,2,2,1,2,2 | ||
| # 1,2,2,1,2 | ||
| # 1,2,2,1 | ||
| # 2,1,2,2,1 | ||
| # 2,1,2,2,1,2 | ||
| # 2,1,2,2,1,2,2 | ||
| # 2,2,1,2,2,1 | ||
| # 2,2,1,2,2,1,2 | ||
| # 2,2,1,2,2,1,2,2 |