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

vector<vector<int> > ret;

vector<int> sub;

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

backtack(candidates, 0, ret, sub, target);

return ret;

}

void backtack(vector<int> &candidates, int index, vector<vector<int> > &ret, vector<int> &sub, int target)

{

if (target == 0)

{

ret.push_back(sub);

}

for (; index < candidates.size() && candidates[index] <= target; index ++)

{

int num = candidates[index];

sub.push_back(num);

backtack(candidates, index + 1, ret, sub, target - num);

sub.pop_back();

// Avoid duplicate situations.

while (index + 1 < candidates.size() && candidates[index] == candidates[index + 1])

{

index ++;

}

}

}

{

int arr[7] = {10, 1, 2, 7, 6, 1, 5};

vector<int> vec(arr + 0, arr + 7);

Solution s;

vector<vector<int> > ret = s.combinationSum2(vec, 8);

for (auto i : ret)

{

for (auto j : i)

{

cout << j << " ";

}

cout << endl;

}