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Author: hogan-tech

0031-next-permutation/0031-next-permutation.py

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+# time complexity: O(n^2)
+# space complexity: O(1)
+from typing import List
+
+
+class Solution:
+    def nextPermutation(self, nums: List[int]) -> None:
+        if nums == sorted(nums, key=lambda x: -x):
+            nums.sort()
+            return
+
+        for i in range(len(nums) - 1, 0, -1):
+            if nums[i - 1] < nums[i]:
+                minIdx, minVal = len(nums), float('inf')
+                for j in range(len(nums) - 1, i - 1, -1):
+                    if nums[j] > nums[i - 1] and nums[j] < minVal:
+                        minVal = nums[j]
+                        minIdx = j
+                nums[i - 1], nums[minIdx] = nums[minIdx], nums[i - 1]
+
+                while True:
+                    swapped = False
+                    for k in range(i, len(nums) - 1):
+                        if nums[k] > nums[k + 1]:
+                            swapped = True
+                            nums[k], nums[k + 1] = nums[k + 1], nums[k]
+                    if swapped == False:
+                        break
+
+                return
+
+
+nums = [1, 2, 3]
+print(Solution().nextPermutation(nums))
+nums = [3, 2, 1]
+print(Solution().nextPermutation(nums))
+nums = [1, 1, 5]
+print(Solution().nextPermutation(nums))