solution.cpp

#include <algorithm>
#include <set>
class Solution
{
public:
	vector<vector<int>> threeSum(vector<int> &nums)
	{
		vector<vector<int>> r;
		if (nums.size() == 0)
			return r;
		sort(nums.begin(), nums.end());
		int cur, left, right;
		cur = 0;
		while (cur < nums.size())
		{
			if (nums[cur] > 0)
				break;
			left = cur + 1;
			right = nums.size() - 1;
			while (left < right)
			{
				int n = nums[cur] + nums[left] + nums[right];
				if (n == 0)
				{
					r.emplace_back(vector<int>({nums[cur], nums[left], nums[right]}));
					int t = left + 1;
					while (t < right && nums[t] == nums[left])
						t++;
					left = t;
					t = right - 1;
					while (t > left && nums[t] == nums[right])
						t--;
					right = t;
				}
				else if (n > 0)
				{
					int t = right - 1;
					while (t > left && nums[t] == nums[right])
						t--;
					right = t;
				}
				else
				{
					int t = left + 1;
					while (t < right && nums[t] == nums[left])
						t++;
					left = t;
				}
			}
			int t = cur + 1;
			while (t < nums.size() && nums[t] == nums[cur])
				t++;
			cur = t;
		}
		return r;
	}
};