WEI-CHENG CHEN

解法

class Solution {
public:
    vector<vector<int>> combinationSum(vector<int>& candidates, int target) {
        vector<vector<int>> ans;
        vector<int> temp;
        backtracking(ans, temp, candidates, target, 0);
        return ans;
    }

    void backtracking(vector<vector<int>> &ans, vector<int> &temp, vector<int>& candidates, int target, int start){
        // 終止條件
        if(target==0){
            ans.push_back(temp);
            return;
        }
        if(target<0) return;

        for(int i=start;i<candidates.size();i++){
            temp.push_back(candidates[i]);
            backtracking(ans, temp, candidates, target-candidates[i], i);
            temp.pop_back();
        }
    }
};