private:
vector<vector<int>> res;
vector<int> path;
vector<int> candidates;
public:
void helper(int start,int target){
if (target<0){
return;
}else if(0==target){
res.push_back(path);
}else{
for(int i=start;i<candidates.size();i++){
if(candidates[i]<=target){
path.push_back(candidates[i]);
helper(i,target-candidates[i]);
path.pop_back();
}
}
}
}
vector<vector<int>> combinationsum(vector<int>& candidates, int target) {
sort(candidates.begin(),candidates.end());
vector<int> path;
this->candidates=candidates;
helper(0,target);
return res;
}
};
/*bool isexist(vector<vector<int>>& res, vector<int> path){
bool flag=false;
for(int i=0;i<res.size();i++){
for(int j=0;j<path.size();j++){
if(res[i][j]!=path[j]){
flag=false;
break;
}
else{
flag=true;
}
}
if(flag==true){
break;
}
}
return flag;
}*/
