第四十五天 Permutations

状态很不好

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

一道很有意思的题目

全排列 深度优先，说了很久，其实理解的不太好，递归也是

先写了代码
刷下题

class Solution:
    def permute(self, nums):
        """
        :type nums: List[int]
        :rtype: List[List[int]]
        """
        self.ans = []
        sub = []
        self.dfs(nums,sub)
        return self.ans
    
    def dfs(self,nums,sub):
        if len(nums) == len(sub):
            self.ans.append(sub[:])
        for m in nums:
            if m in sub:
                continue
            sub.append(m)
            self.dfs(nums,sub)
            sub.remove(m)