47. Permutations II

Q. No. -> 47. Permutations II
Ans->
class Solution {
public:
   void solve(vector<int>& nums,vector<vector<int>>& output, int i){
       if( i>=nums.size()){
         output.push_back(nums);
         return ;
       }
       // most important.. loop should be started from j =i..
       for(int j=i;j<nums.size();j++){
           swap(nums[i],nums[j]);
           solve(nums,output,i+1);
           //backtracking..
           swap(nums[i],nums[j]);

       }
   }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
       vector<vector<int>> output;
       solve(nums,output,0);
        set<vector<int>>checking;
        for( auto i : output){
            checking.insert(i);
        }
       vector<vector<int>> result;
        for( auto i : checking){
            result.push_back(i);
        }
        return result;
    }
};