leetcode ThreeSums

import java.util.*;

public class ThreeSum {
  /**
   * Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0?
   * Find all unique triplets in the array which gives the sum of zero.
   *
   * Note:
   *
   * The solution set must not contain duplicate triplets.
   *
   * Example:
   *
   * Given array nums = [-1, 0, 1, 2, -1, -4],
   *
   * A solution set is:
   * [
   *   [-1, 0, 1],
   *   [-1, -1, 2]
   * ]
   */
  public static List<List<Integer>> threeSum(int[] nums) {
    List<List<Integer>> ans = new LinkedList<>();
    if (nums.length < 3) return ans;
    Arrays.sort(nums);
    for (int i=0; i<nums.length; i++) {
      int left = nums[i+1];
      int right = nums[nums.length-1];
      while (left < right) {
        if (nums[i] + nums[left] + nums[right] == 0) {
          ans.add(Arrays.asList(nums[i], nums[left], nums[right]));
        }
      }
    }
    return ans;
  }

  public static void main(String[] args) {
    for (List<Integer> l : threeSum(new int[]{-4,-2,-2,-2,0,1,2,2,2,3,3,4,4,6,6})) {
      for (int i: l) {
        System.out.print(i + " ");
      }
      System.out.println();
    }
  }
}