LeetCode--Combination Sum II

class Solution {
public:
vector<vector<int> >ans;
vector<vector<int> > combinationSum2(vector<int> &num, int target) {
if(num.size() == 0)
return ans;
sort(num.begin(),num.end());
vector<int> res;
vector<int> index;
calSum(num,target,0,res,index);
return ans;
}
void calSum(vector<int> &num,int target,int s,vector<int> &res,vector<int> &index)
{
if(target < 0)
return;
if(target == 0)
{
ans.push_back(res);
return;
}
int i;
for(i = s ; i < num.size() ; ++i)
{
if(i >0 && index[index.size()-1] != i-1 && num[i] == num[i-1])
continue;
index.push_back(i);
res.push_back(num[i]);
calSum(num,target-num[i],i+1,res,index);
res.pop_back();
index.pop_back();
}
return;
}
};