Leetcode 40. Combination Sum II

题目：

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]
]                                                                                                                              

去重问题还要优化，最蠢的方法了

class Solution {
public:
    void f(vector<vector<int>> &re,map<int,int> &flag,int cur,int target,vector<int> &tmp){
        if(cur == target) {
            re.push_back(tmp);
            return ;
        } else {
            for(map<int,int>::iterator it = flag.begin(); it != flag.end(); it++ ){
                if(it->first<=target-cur){
                     if(it->second != 0){
                         it->second--;
                         tmp.push_back(it->first);
                         f(re,flag,cur+it->first,target,tmp);
                         it->second++;
                         tmp.pop_back();
                     } 
                } else {
                    break;
                }
               
            }
        }
    }
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        vector<vector<int>> re;
        map<int,int> flag;
        vector<int> tmp;
        for(auto val:candidates) flag[val]++;
        f(re,flag,0,target,tmp);
	for(int i = 0; i < re.size();i++){
	   sort(re[i].begin(),re[i].end());
        } 
        set<vector<int>> ret;
        for(auto val:re) ret.insert(val);
        re.clear();
        for(auto val:ret) re.push_back(val);
        return re;
    }
};