leetcode40

感觉和39题一波一样的思想。。。。。easy

#include<iostream>
#include<vector>
using namespace std;
class Solution {
public:
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        if(candidates.size() < 0)
    		return {};
    	sort(candidates.begin(), candidates.end());
    	if(target < candidates[0])
    		return {};
        vector<vector<int> > result;
        vector<int> temp;
        int sum = 0;
        getBacking(result, temp, candidates, sum, 0, target);
        sort(result.begin(), result.end());
        auto ite = unique(result.begin(), result.end());
        result.erase(ite,result.end());
        return result;
    }
    bool getBacking(vector<vector<int> >& result,vector<int>& temp,vector<int> nums, int sum, int k, int target){
    	if(sum > target){
    		return false;
    	}else if(sum == target){
    		result.push_back(temp);
    		return false;
    	}else{
    		for(int i=k;i<nums.size();i++){
    			bool flag = true;
    			temp.push_back(nums[i]);
    			sum += nums[i];
    			if(i != nums.size()-1){
    				flag = getBacking(result, temp, nums, sum, i+1, target);	
    			}
    			if(i == nums.size()-1 && sum == target){
    				result.push_back(temp);
    			}
    			sum -= nums[i];
    			temp.pop_back();
    			if(!flag)
    				break;
    		}
    		return true;
    	}
    }
};
int main(){

	return 0;
}