import java.util.*;

public class ThreeSum {

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

List<List<Integer>> result = new ArrayList<>();

Arrays.sort(nums); // Sort the array to easily handle duplicates

for (int i = 0; i < nums.length - 2; i++) {

// Skip duplicates

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

int target = -nums[i];

int left = i + 1;

int right = nums.length - 1;

while (left < right) {

int sum = nums[left] + nums[right];

if (sum == target) {

result.add(Arrays.asList(nums[i], nums[left], nums[right]));

// Skip duplicates

while (left < right && nums[left] == nums[left + 1]) left++;

while (left < right && nums[right] == nums[right - 1]) right--;

// Move pointers

left++;

right--;

} else if (sum < target) {

left++;

} else {

right--;

}

}

}

return result;

}

public static void main(String[] args) {

ThreeSum solution = new ThreeSum();

int[] nums = {-1, 0, 1, 2, -1, -4};

List<List<Integer>> result = solution.threeSum(nums);

System.out.println(result);

}

}