class Solution {
    public List<List<Integer>> threeSum(int[] nums) {
        Set<List<Integer>> set = new HashSet<>();
        Arrays.sort(nums);
        for(int i=0; i<nums.length-2; i++){
            int j=i+1, k=nums.length-1;
            while(j<k){
                int sum=nums[i]+nums[j]+nums[k];
                if(sum==0) set.add(Arrays.asList(nums[i], nums[j++], nums[k--]));
                else if(sum>0) k--;
                else j++;
            }
        }
        return new ArrayList<>(set);
    }
}