Leetcode 40. Combination Sum II (Medium) (cpp)

Leetcode 40. Combination Sum II (Medium) (cpp)

Tag: Array, Backtracking

Difficulty: Medium

/*40. Combination Sum II (Medium)Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.Each number in C may only be used once in the combination.Note:All numbers (including target) will be positive integers.The solution set must not contain duplicate combinations.For example, given candidate set [10, 1, 2, 7, 6, 1, 5] and target 8, A solution set is: [  [1, 7],  [1, 2, 5],  [2, 6],  [1, 1, 6]]*/class Solution {public:    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {        vector<vector<int>> res;        vector<int> res_sub;        sort(candidates.begin(), candidates.end());        match(candidates, target, 0, res_sub, res);        return res;    }    void match(vector<int>& candidates, int target, int start, vector<int>& res_sub, vector<vector<int>>& res) {        if (target == 0) {            res.push_back(res_sub);            return;        }        for (int i = start; i < candidates.size() && candidates[i] <= target; i++) {            if (i > start && candidates[i] == candidates[i- 1]) continue;            res_sub.push_back(candidates[i]);            match(candidates, target - candidates[i], i + 1, res_sub, res);            res_sub.pop_back();        }    }};