LeetCode 40 组合总和 II

class Solution {
public:
    vector<vector<int>> res;
    vector<int> path;
    int sum;

    void dfs(int start, vector<int>& candidates, int target) {
        if (sum > target) return;

        if (sum == target) {
            res.push_back(path);
            return;
        }

        for (int i = start; i < candidates.size(); i ++) {

            if (i > start && candidates[i] == candidates[i - 1]) continue; //去重，同一树层上不能使用相同的数

            path.push_back(candidates[i]);
            sum += candidates[i];
            dfs(i + 1, candidates, target);
            sum -= candidates[i];
            path.pop_back();
        }
    }

    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        sort(candidates.begin(), candidates.end());
        dfs(0, candidates, target);

        
        return res;
    }
};