[python-next-permutation] next permuation of list of elements #python #algorithm

next_permutation.py

def next_permutation(nums):
    """
    :type nums: List[int]
    :rtype: void Do not return anything, modify nums in-place instead.
    """
    if not nums: return nums
    l = len(nums)
    i, j = l - 2, l - 1
    while i >= 0 and nums[i] >= nums[i + 1]:
        i -= 1

    if i == -1:
        nums = nums[::-1]
        return

    while j > i and nums[j] <= nums[i]:
        j -= 1
    nums[i], nums[j] = nums[j], nums[i]
    nums[i + 1:] = nums[i + 1:][::-1]