36 lines
1.0 KiB
Python
36 lines
1.0 KiB
Python
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class Solution:
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def nextPermutation(self, nums: List[int]) -> None:
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"""
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Do not return anything, modify nums in-place instead.
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"""
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# Find start of strictly decreasing section from the right
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# and identify the position of element right before it
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right = len(nums) - 1
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while right > 0:
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if nums[right - 1] < nums[right]:
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break
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right -= 1
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swap_pos = right - 1
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# Array is already in decreasing order, hence we return the reverse
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if swap_pos < 0:
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nums.reverse()
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return
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# Find next greatest element from [swap_pos + 1, n)
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right = len(nums) - 1
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while right > swap_pos:
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if nums[right] > nums[swap_pos]:
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break
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right -= 1
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nums[swap_pos], nums[right] = nums[right], nums[swap_pos]
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# Reverse [swap_pos + 1, n)
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nums[swap_pos + 1:] = nums[:swap_pos:-1]
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