Leetcode | 15 3Sum

15 3Sum(三数之和为0）

【题目】链接
【代码】

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) 
    {
        vector<vector<int>> res;
        sort(nums.begin(), nums.end());
        for (int k = 0; k < nums.size(); ++k) 
        {
            if (nums[k] > 0) 
            	break;
            if (k > 0 && nums[k] == nums[k - 1]) 
            	continue;
            int target = 0 - nums[k];
            int i = k + 1, j = nums.size() - 1;
            while (i < j) 
            {
                if (nums[i] + nums[j] == target) 
                {
                    res.push_back({nums[k], nums[i], nums[j]});
                    while (i < j && nums[i] == nums[i + 1]) 
                    	++i;
                    while (i < j && nums[j] == nums[j - 1]) 
                    	--j;
                    ++i;
                    --j;
                } 
                else if (nums[i] + nums[j] < target) 
                	++i;
                else 
                	--j;
            }
        }
        return res;
    }
};