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Copy pathSolution.py
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35 lines (29 loc) · 1.1 KB
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from _ast import List
class Solution:
def permuteUnique(self, nums: List[int]) -> List[List[int]]:
ans = []
if nums is not None and len(nums) > 0:
self.dfs(nums, 0, ans)
return ans
def dfs(self, nums: List[int], index: int, ans: List[int]) -> None:
if index >= len(nums):
oneAns = []
for i in range(len(nums)):
oneAns.append(nums[i])
ans.append(oneAns)
return
for i in range(index, len(nums)):
# nums[index]和nums[i-1]中有与nums[i]相同的元素，那么就不进行交换
if self.seen(nums, index, i):
continue
self.swap(nums, index, i)
self.dfs(nums, index + 1, ans)
self.swap(nums, index, i)
def seen(self, nums: List[int], start: int, end: int) -> bool:
if start < end:
for i in range(start, end):
if nums[i] == nums[end]:
return True
return False
def swap(self, nums: List[int], i: int, j: int):
nums[i], nums[j] = nums[j], nums[i]