算法流程图中表示算法起止的图形(算法图解下个排列)
算法流程图中表示算法起止的图形(算法图解下个排列)第四步:从 (i 1) 位置开始颠倒序列def nextPermutation(nums: List[int]) -> None: """ Do not return anything modify nums in-place instead. """ n = len(nums) # step 1: find the larget i such that A[i] < A[i 1] found = False for i in range(n-2 -1 -1): if nums[i] < nums[i 1]: found = True break # Notice: if
给定一个单词或整数数组,按字典顺序排列找到下一个排列例如,“gfg”的下一个排列是“ggf”,[1 2 3] 的下一个排列是 [1 3 2]。
第一步:从后往前找到第一个破坏单调递增性质的位置(i, i 1)
第二步:在 i 后面找到位置最靠后比 A[i] 大的元素A[j]
第三步:交换 A[i] 和 A[j]
第四步:从 (i 1) 位置开始颠倒序列
def nextPermutation(nums: List[int]) -> None:
"""
Do not return anything modify nums in-place instead.
"""
n = len(nums)
# step 1: find the larget i such that A[i] < A[i 1]
found = False
for i in range(n-2 -1 -1):
if nums[i] < nums[i 1]:
found = True
break
# Notice: if can't find any we have the largest permutation
if not found: return nums.reverse()
# step 2: find the largest index j such that A[i] < A[j]
for k in range(i 1 n):
if nums[i] < nums[k]:
j = k
# step 3: swap i and j
nums[i] nums[j] = nums[j] nums[i]
# step 4: reverse A[i 1] to the end
for k in range(i 1 (i n)//2 1):
nums[k] nums[n i-k] = nums[n i-k] nums[k]
return nums
Follow-up: 怎样找前一个排列呢?