LeetCode – Refresh – Combination Sum

This is a classical combination question. 

 

class Solution {
public:
    void getComb(vector<vector<int> > &result, const vector<int> &num, vector<int> current, int sum, int target, int start) {
        if (sum == target) {
            result.push_back(current);
            return;
        }
        if (sum > target) {
            return;
        }
        for (int i = start; i < num.size(); i++) {
            current.push_back(num[i]);
            getComb(result, num, current, sum + num[i], target, i);
            current.pop_back();
        }
    }
    vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
        vector<vector<int> > result;
        sort(candidates.begin(), candidates.end());
        getComb(result, candidates, vector<int> (), 0, target, 0);
        return result;
    }
};