30 Day Challenge Day 14 | Leetcode 40. Combination Sum II

题解

Medium | Backtracking

class Solution {
public:
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        sort(candidates.begin(), candidates.end());
        vector<vector<int>> sols;
        vector<int> sol;
        helper(candidates, target, 0, 0, sol, sols);
        return sols;
    }
    
    void helper(vector<int>& candidates, int target, int index, int sum, vector<int>& sol, vector<vector<int>>& sols) {
        if(sum == target) {
            sols.push_back(sol);
            return;
        }
        
        if(sum > target) return;
        
        for(int i = index; i < candidates.size(); i++) {
            if(i > index && candidates[i] == candidates[i-1]) continue;
            sol.push_back(candidates[i]);
            helper(candidates, target, i+1, sum+candidates[i], sol, sols);
            sol.pop_back();
        }
    }
};