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;
}
};