vector<vector<int> > threeSum(vector<int>& nums) {

vector<vector<int> > ret;

int n = nums.size();

if (n < 3)

{

return ret;

}

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

for (int i = 0; i < n; i ++)

{

// Avoid repeate situation.

if (i > 0 && nums[i] == nums[i - 1])

{

continue;

}

int l = i + 1, r = n - 1;

while (l < r)

{

int sum = nums[i] + nums[l] + nums[r];

if (sum == 0)

{

ret.push_back(vector<int>{nums[i], nums[l], nums[r]});

// Avoid repeate elements.

while (nums[l] == nums[l + 1])

{

l ++;

}

while (nums[r] == nums[r - 1])

{

r --;

}

l ++;

r --;

}

else if (sum > 0)

{

r --;

}

else

{

l ++;

}

}

}

return ret;

}

{

int arr[6] = {-1, 0, 1, 2, -1, -4};

vector<int> vec(arr + 0, arr + 6);

Solution s;

vector<vector<int> > ret = s.threeSum(vec);

for (auto i : ret)

{

for (auto j : i)

{

cout << j << " ";

}

cout << endl;

}