题目描述

blablabla

样例

blablabla

算法1

DFS

C++ 代码

class Solution {
vector<vector<int>> res;
vector<int> onePermutation;
vector<bool> visited;
int n;
set<vector<int>> hashTable;         //去重

public:
    vector<vector<int>> permutation(vector<int>& nums) {
        n = nums.size();
        onePermutation = vector<int>(0);
        visited = vector<bool>(n);
        DFS(nums, 0, n, visited, onePermutation, res);
        for(auto permu : hashTable) {
            res.push_back(permu);
        }
        return res;
    }

    void DFS(vector<int>& nums, int pos, int n, vector<bool>& visited, vector<int>& onePermutation, vector<vector<int>>& res) {
        if(pos == n) {
            hashTable.insert(onePermutation);
            return ;
        }
        for(int i = 0; i < n; ++i) {
            if(visited[i] == false) {
                onePermutation.push_back(nums[i]);
                visited[i] = true;
                DFS(nums, pos + 1, n, visited, onePermutation, res);
                visited[i] = false;
                onePermutation.pop_back();
            }
        }
    }
};