16. 3Sum Closest

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.
For example, given array S = {-1 2 1 -4}, and target = 1. The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

public class Solution {
    public int threeSumClosest(int[] nums, int target) {
        
        long mindiff = Long.MAX_VALUE;
        long closet = 0;
        Arrays.sort(nums);
        
        for(int i=0;i<nums.length-2;i++)
           {
               
               int start = i+1,end =nums.length-1;
               
               while(start<end)
               {
                   long sum = nums[i] + nums[start] + nums[end];
                   long newdiff = Math.abs(sum-target);
                   if(newdiff == 0)
                       return (int)sum;
                   if(newdiff<mindiff)
                      {
                          mindiff = newdiff;
                          closet = sum;
                      }
                   if(sum>target)
                      end--;
                   else if(sum<target)
                      start++;
               }
           }
        return (int)closet;
    }
}