Leetcode Combination Sum II

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

Each number in C may only be usedonce 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] 

      递归遍历，看看和是否等于8，注意在同一层中，两个相等值只能选择一次。

class Solution {public:    void combin(vector<vector<int> > &res,vector<int> &temp,vector<int> &num,int target,int cur){        if(target==0){            res.push_back(temp);            return;        }else if(target<0)return;        else{            for(int i=cur;i<num.size();i++){                if(i!=cur&&num[i]==num[i-1])continue; //同一层中，两个相等值只能选择一次                temp.push_back(num[i]);                combin(res,temp,num,target-num[i],i+1);                temp.pop_back();            }        }    }    vector<vector<int> > combinationSum2(vector<int> &num, int target) {        vector<vector<int> > res;        if(num.size()==0)return res;        sort(num.begin(),num.end());        vector<int> temp;        combin(res,temp,num,target,0);        return res;    }};