#define _ALLOW_COMPILER_AND_STL_VERSION_MISMATCH

#include <iostream>
#include <vector>
#include <unordered_set>
using namespace std;

class Solution {
public:
    unordered_set<vector<int>> result;
    vector<int> path;
    vector<bool> visited;
    void dfs(const vector<int>& nums, vector<int>& path, vector<bool>& visited){
        if(path.size() == nums.size()) {
            result.insert(path);
            return;
        }
        //use index
        for(int i = 0; i < nums.size(); i++){
            if(!visited[i]){
                path.push_back(nums[i]);
                visited[i] = true;
                dfs(nums, path, visited);
                path.pop_back();
                visited[i] = false;
            }
        }                   
    }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        visited.resize(nums.size(), false);
        dfs(nums, path, visited);
        vector<vector<int>> res(result.begin(), result.end());
        return res;
    }
};

int main(){
    
}