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 helper(vector<vector<int> > &svec, vector<int> &candidates, vector<int> &vec, int start, int sum, int target)
{
if(sum == target)
{
if(find(svec.begin(), svec.end(), vec) == svec.end())
svec.push_back(vec);

return;
}

for(int i = start; i < candidates.size(); ++ i)
{
if(sum + candidates[i] <= target)
{
vec.push_back(candidates[i]);
helper(svec, candidates, vec, i + 1, sum + candidates[i], target);
vec.pop_back();
}
}

}
vector<vector<int> > combinationSum2(vector<int>& candidates, int target)
{
vector<int> vec;
vector<vector<int> > svec;
int len = candidates.size();
if(len == 0)
{
return svec;
}
sort(candidates.begin(), candidates.end());
helper(svec, candidates, vec, 0, 0, target);
return svec;
}
};