leetcode15– Sum of three numbers

Topic link ：leetcode15

Title Description

title

Title details address ：bilibili

Code

class Solution {
    
    public List<List<Integer>> threeSum(int[] nums) {
    
        List<List<Integer>> arrayList = new ArrayList<>();

        Arrays.sort(nums);

        for (int i = 0; i < nums.length; i++) {
    

            if (i > 0 && nums[i] == nums[i-1]){
    
                continue;
            }

            int left = i+1;
            int right = nums.length - 1;

            while (left < right){
    
                int sum = nums[i] + nums[left] + nums[right];
                if (sum > 0){
    
                    right--;
                }else if (sum < 0){
    
                    left ++;
                }else {
    
                    arrayList.add(Arrays.asList(nums[i],nums[left],nums[right]));
                    while (left < right && nums[right] == nums[right-1]){
    
                        right--;
                    }
                    while (left < right && nums[left] == nums[left+1]){
    
                        left++;
                    }
                    right--;
                    left++;
                }
            }
        }
        return arrayList;
    }
}

Reference resources

https://leetcode.cn/problems/3sum/
https://programmercarl.com/0015.%E4%B8%89%E6%95%B0%E4%B9%8B%E5%92%8C.html#%E5%93%88%E5%B8%8C%E8%A7%A3%E6%B3%95