ThreeSumProblemAnother.java

package swe;

import java.util.*;

public class ThreeSumProblemAnother {
    public static List<List<Integer>> threeSum(int[] nums) {

        Arrays.sort(nums);
        Set<List<Integer>> allThreeSum = new HashSet<>();
        for (int i = 0; i < nums.length - 2; i++) {
            int left = i + 1;
            int right = nums.length - 1;

            while (left < right) {
                int sum = nums[i] + nums[left] + nums[right];

                if (sum == 0) {
                    allThreeSum.add(Arrays.asList(nums[i], nums[left], nums[right]));
                    left++;
                    right--;
                } else if (sum < 0) {
                    left++;
                } else {
                    right--;
                }
            }
        }
        return new ArrayList<>(allThreeSum);
    }

    public static void main(String[] args) {
        int[] nums = {-3, -1, 1, 0, 2, 10, -2, 8};
        List<List<Integer>> result = threeSum(nums);
        for (List<Integer> triplet : result) {
            System.out.println(triplet);
        }
    }
}