leetcode 40: Combination Sum II

class Solution {
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<vector<int> > res;
vector<int> set;
sort(candidates.begin(),candidates.end());
helper(candidates,0,target,set,res);
return res;
}
void helper(vector<int>& candidates,int idx,int target,vector<int>& set,vector<vector<int> >& res){
for(int i=idx;i<candidates.size()&&candidates[i]<=target;i++)
{
if(i==idx||candidates[i]!=candidates[i-1])//The cases with repeat numbers are considered in the recursion, so they should not be considered in the loop
{
set.push_back(candidates[i]);
if(candidates[i]==target)
{
res.push_back(set);
set.pop_back();
break;
}
else
{
helper(candidates,i+1,target-candidates[i],set,res);
set.pop_back();
}
}
}
}
};