void helper(vector<int>& candidates,vector<int>& combination,vector<vector<int>>& ans,int target,int start){

if(target==0){

ans.push_back(combination);

return;

}

for(int i=start;i<candidates.size();i++){

if(candidates[i]>target) break;

if(i>start && candidates[i]==candidates[i-1]) continue;

combination.push_back(candidates[i]);

helper(candidates,combination,ans,target-candidates[i],i+1);

combination.pop_back();

}

}

vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {

vector<vector<int>> ans;

vector<int> combination;

sort(candidates.begin(),candidates.end());

helper(candidates,combination,ans,target,0);

return ans;

}