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 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  DFS(vector<int> &candidates, int target, int start, int sum, vector<int> &tp){

    	if(sum == target){

			res.push_back(tp);

			return;

		}

		for(int i = start; i< candidates.size(); ++i){

		    if(i != start && candidates[i] == candidates[i-1])

					continue;

			if(candidates[i] + sum <= target){

				tp.push_back(candidates[i]);

				DFS(candidates, target, i+1, sum+candidates[i], tp);

				tp.pop_back();

			}

		}

	}

    vector<vector<int> > combinationSum2(vector<int> &candidates, int target) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        res.clear();

		int len = candidates.size();

		if(len < 1 || target <1) return res;

		sort(candidates.begin(), candidates.end());

		vector<int> tp;

		DFS(candidates, target, 0, 0, tp);

		return res;

		

    }

private:

	vector<vector<int>> res;

};