Leetcode Combination Sum II

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums toT.

Each number in C may only be used once in the combination.

Note:

• All numbers (including target) will be positive integers.
• Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
• 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] 

暴力搜索

class Solution {
public:
  vector<vector<int> > res;
    vector<int> path;
    vector<int> candidates;
    int target;
    
    void solve(int start, int sum){
        if(sum > target) return;
        if(sum == target){
            if(find(res.begin(),res.end(),path)==res.end())
                res.push_back(path);
            return;
        }
        for(int i = start; i < candidates.size(); ++ i){
            path.push_back(candidates[i]);
            solve(i+1,sum+candidates[i]);
            path.pop_back();
        }
    }

    vector<vector<int> > combinationSum2(vector<int> &candidates, int target) {
        this->candidates = candidates;
        this->target = target;
        sort(this->candidates.begin(),this->candidates.end());
        solve(0,0);
        return res;
    }
};