[LeetCode]题解（python）：046-Permutations

题目来源

https://leetcode.com/problems/permutations/

Given a collection of distinct numbers, return all possible permutations.

For example,
[1,2,3] have the following permutations:
[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].

题意分析

Input: a list

Output: a permutations

Conditions:全排列

题目思路

递归解决。注意到python取list的若干位很方便，分片~然后仔细发现不单是全排序，而且还是字典序（因为每一次遍历都是从小到大的，遍历顺序取决~）

AC代码（Python）

 1 class Solution(object):
 2     def permute(self, nums):
 3         """
 4         :type nums: List[int]
 5         :rtype: List[List[int]]
 6         """
 7         if len(nums) == 1:
 8             return [nums]
 9         res = []
10         for i in range(len(nums)):
11             for j in self.permute(nums[:i] + nums[i+1:]):
12                 res.append([nums[i]] + j)
13         return res

时间： 2024-10-12 18:26:29

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