一、题目

给定一个没有重复数字的序列，返回其所有可能的全排列。

示例1

输入: [1,2,3] 输出: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ]

二、代码

python

itertools库

def permute(nums): return list(itertools.permutations(nums))

回溯算法

def permute(nums): if not nums: return res = [] n = len(nums) visited = [0] * n def helper1(temp_list,length): if length == n: res.append(temp_list) for i in range(n): if visited[i] : continue visited[i] = 1 helper1(temp_list+[nums[i]],length+1) visited[i] = 0 def helper2(nums,temp_list,length): if length == n: res.append(temp_list) for i in range(len(nums)): helper2(nums[:i]+nums[i+1:],temp_list+[nums[i]],length+1) helper1([],0) return res