leetcode记录15. 3Sum

leetcode记录15. 3Sum

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        
        sort(nums.begin(), nums.end());
        vector<vector<int>> result;
        if (nums.size() < 3) return {};
        
        for(int i = 0; i < (nums.size() - 2); i++)
        {
            int j = i + 1;
            int k = nums.size() - 1;
            while(j < k)
            {
                int sum = nums[i] + nums[j] + nums[k];
                if(sum == 0)
                {
                    vector<int> temp;
                    temp.push_back(nums[i]);
                    temp.push_back(nums[j]);
                    temp.push_back(nums[k]);
                    result.push_back(temp);
                    int l = nums[j];
                    int r = nums[k];
                    while(l == nums[j] && j < k)
                    {
                        j++;
                    }
                    while(r == nums[k] && j < k)
                    {
                        k--;
                    }

                }
                else if(sum < 0)
                {
                    j++;
                }
                else if(sum > 0)
                {
                    k--;
                }
            }
            
            while(i < nums.size() - 2)
            {
                if(nums[i] == nums[i+1])
                {
                    i++;
                }
                else
                {
                    break;
                }
            }
        }
        
        return result; 
    }
};