46. Permutations

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

Example:

Input: [1,2,3]
Output:
[
  [1,2,3],
  [1,3,2],
  [2,1,3],
  [2,3,1],
  [3,1,2],
  [3,2,1]
]


求数组的全排列


C++：

class Solution {
public:
    vector<vector<int>> permute(vector<int>& nums) {
        vector<vector<int>> permutes ;
        vector<int> permute ;
        vector<bool> visit(nums.size() , false) ;
        backtracking(nums,permutes,permute,visit) ;
        return permutes ;
    }
    
    void backtracking(vector<int>& nums ,vector<vector<int>>& permutes,vector<int>& permute,vector<bool>& visit){
        if (permute.size() == nums.size()){
            permutes.push_back(permute) ;
            return ;
        }
        for(int i = 0 ; i < nums.size() ; i++){
            if (visit[i]){
                continue ;
            }
            visit[i] = true ;
            permute.push_back(nums[i]) ;
            backtracking(nums,permutes,permute,visit) ;
            permute.pop_back() ;
            visit[i] = false ;
        }
    }
};