CombinationSum2.cpp

class Solution {
public:

  void combinationHelper(int idx, vector<int>& arr, int target, vector<vector<int>>& ans, vector<int> ds){
        if(target==0){
            ans.push_back(ds);
            return;
        }

        for(int i=idx; i<arr.size(); i++){
            if(i>idx && arr[i]==arr[i-1])continue;
            if(arr[i]>target) break;
            ds.push_back(arr[i]);
            combinationHelper(i+1, arr, target-arr[i], ans, ds);
            ds.pop_back();
        }
    }


    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
       // a temp storage // a ans vect
       sort(candidates.begin(), candidates.end());
       vector<vector<int>> ans;
       vector<int> ds;
       combinationHelper(0, candidates, target, ans, ds); 
       return ans;
    }
};