Leecode 15.题：三数之和

public static List> threeNumSum(int[] nums){
    List> result = new ArrayList<>();
    Arrays.sort(nums);
    for(int i=0;i 0 && nums[i] == nums[i-1]){
              continue;
          }
          int j = i+1;
          int k = nums.length-1;
          while ( i i+1 && nums[j] == nums[j - 1]) && (k< nums.length -1 && nums[k] == nums[k + 1])){
                  j++;
                  k--;
                  continue;
              }
              int sum = nums[i] + nums[j] + nums[k];
             if(sum == 0){
                 result.add(Arrays.asList(nums[i] ,nums[j] , nums[k]));
                 j++;
                 k--;
             }else if(sum > 0){
                 k--;
             }else{
                 j++;
             }
          }
    }
    return result;
}