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).

Analysis: Almost the same as the 3Sum problem. 

public class Solution {
    public int threeSumClosest(int[] num, int target) {
        Arrays.sort(num);
        int result = Integer.MIN_VALUE;
        for(int i=0; i<=num.length-3; i++) {    // at least 3 elements
            if(i>0 && num[i]==num[i-1]) continue;   // avoid duplicate
            int low=i+1, high=num.length-1;
            while(low < high) {
                int current = num[low]+num[high]+num[i];
                if(result==Integer.MIN_VALUE || Math.abs(target-result)>Math.abs(target-current)) result=current;
                if(current > target) {
                    high--;
                    while(low<high && num[high]==num[high+1]) high--;   // avoid unnecessary check
                }
                else if(current < target) {
                    low++;
                    while(low<high && num[low]== num[low-1]) low++;     // avoid unnecessary check
                }
                else if(current==target) return target;
            }
        }
        return result;
    }
}