Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (including target) will be positive integers. Elements in a combination (a1, a2, … , ak) must be in non-descending orde…

Combination sum.cpp

class Solution {
public:
    vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        sort(candidates.begin(), candidates.end());
        vector<int> curResult;
        vector<vector<int> > results;
        solve(candidates, target, results, 0, curResult);
        return results;
    }
    
    
    void solve(vector<int>& candidates, int target, vector<vector<int> >& results, int cur, vector<int>& curResult) {
        if(target < 0) {
            return;
        } else if(target == 0) {
            results.push_back(curResult);
            return;
        }
        
        
        for(int i = cur; i < candidates.size(); ++i) {
            curResult.push_back(candidates[i]);
            solve(candidates, target - candidates[i], results, i, curResult);
            curResult.pop_back();
        }
        
    }
};