leetcode[39]Combination Sum

Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.

The same repeated number may be chosen from C unlimited number of times.

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 2,3,6,7 and target 7, 
A solution set is: 
[7] 
[2, 2, 3] 

class Solution {

public:

void searchTarget(vector<vector<int>> &res, vector<int> temp, vector<int> &candidates, int target, int index)

{

    if (target==0)res.push_back(temp);

    else

    {

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

        {

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

                continue;

            if (target>=candidates[i])

            {

                temp.push_back(candidates[i]);

                searchTarget(res,temp,candidates,target-candidates[i],i);

                temp.pop_back();

            }

        }

    }

}

vector<vector<int>> combinationSum(vector<int> &candidates, int target) 

{

    vector<vector<int>> res;

    vector<int> temp;

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

    searchTarget(res,temp,candidates,target,0);

    return res;

}

};