@@ -160,73 +160,34 @@ class Solution {
160160```
161161
162162## Python
163- >直接使用sorted()不符合题意
163+ >直接使用sorted()会开辟新的空间并返回一个新的list,故补充一个原地反转函数
164164```python
165165class Solution:
166166 def nextPermutation(self, nums: List[int]) -> None:
167167 """
168168 Do not return anything, modify nums in-place instead.
169169 """
170- for i in range(len(nums)-1, -1, -1):
171- for j in range(len(nums)-1, i, -1):
170+ length = len(nums)
171+ for i in range(length - 1, -1, -1):
172+ for j in range(length - 1, i, -1):
172173 if nums[j] > nums[i]:
173174 nums[j], nums[i] = nums[i], nums[j]
174- nums[i+1:len(nums)] = sorted(nums[i+1:len(nums)])
175- return
176- nums.sort()
177- ```
178- >另一种思路
179- ```python
180- class Solution :
181- '''
182- 抛砖引玉:因题目要求"必须原地修改,只允许使用额外常数空间",python内置sorted函数以及数组切片+sort()无法使用。
183- 故选择另一种算法暂且提供一种python思路
184- '''
185- def nextPermutation(self, nums: List[ int] ) -> None:
186- """
187- Do not return anything, modify nums in-place instead.
188- """
189- length = len(nums)
190- for i in range(length-1, 0, -1):
191- if nums[ i-1] < nums[ i] :
192- for j in range(length-1, 0, -1):
193- if nums[ j] > nums[ i-1] :
194- nums[ i-1] , nums[ j] = nums[ j] , nums[ i-1]
195- break
196- self.reverse(nums, i, length-1)
197- break
198- if n == 1:
199- # 若正常结束循环,则对原数组直接翻转
200- self.reverse(nums, 0, length-1)
201- 202- def reverse(self, nums: List[int], low: int, high: int) -> None:
203- while low < high:
204- nums[low], nums[high] = nums[high], nums[low]
205- low += 1
206- high -= 1
207- ```
208- >上一版本简化版
209- ```python
210- class Solution(object):
211- def nextPermutation(self, nums: List[int]) -> None:
212- n = len(nums)
213- i = n-2
214- while i >= 0 and nums[i] >= nums[i+1]:
215- i -= 1
216-
217- if i > -1: // i==-1,不存在下一个更大的排列
218- j = n-1
219- while j >= 0 and nums[j] <= nums[i]:
220- j -= 1
221- nums[i], nums[j] = nums[j], nums[i]
175+ self.reverse(nums, i + 1, length - 1)
176+ return
177+ self.reverse(nums, 0, length - 1)
222178
223- start, end = i+1, n-1
224- while start < end:
225- nums[start], nums[end] = nums[end], nums[start]
226- start += 1
227- end -= 1
228-
229- return nums
179+ def reverse(self, nums: List[int], left: int, right: int) -> None:
180+ while left < right:
181+ nums[left], nums[right] = nums[right], nums[left]
182+ left += 1
183+ right -= 1
184+
185+ """
186+ 265 / 265 个通过测试用例
187+ 状态:通过
188+ 执行用时: 36 ms
189+ 内存消耗: 14.9 MB
190+ """
230191```
231192
232193## Go
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