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

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

Arrays.sort(nums);

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

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

int low = i + 1;

int high = nums.length - 1;

while (low < high) {

int threeSum = nums[i] + nums[low] + nums[high];

if (threeSum < 0) {

low = low + 1;

} else if (threeSum > 0) {

high = high - 1;

} else {

result.add(Arrays.asList(nums[i], nums[low], nums[high]));

while (low < high && nums[low] == nums[low + 1]) low++;

while (low < high && nums[high] == nums[high - 1]) high--;

low = low + 1;

high = high - 1;

}

}

}

return result;

}