class Solution {

//2 pointers

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

Arrays.sort(nums);

LinkedList<List<Integer>> sol = new LinkedList<List<Integer>>();

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

if (i == 0 || (i > 0 && nums[i] != nums[i - 1])) {

int target = 0 - nums[i];

int left = i + 1;

int right = nums.length - 1;

while (left < right) {

if (nums[left] + nums[right] == target) {

ArrayList<Integer> miniSol = new ArrayList<>();

miniSol.add(nums[i]);

miniSol.add(nums[left]);

miniSol.add(nums[right]);

sol.add(miniSol);

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

left++;

}

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

right--;

}

left++;

right--;

} else if (nums[left] + nums[right] > target) {

right--;

} else {

left++;

}

}

}

}

return sol;

}

}