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 to T.

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] 

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