[LeetCode]16 3Sum Closest

https://oj.leetcode.com/problems/3sum-closest/

http://fisherlei.blogspot.com/2013/01/leetcode-3sum-closest-solution.html

public class Solution {
    public int threeSumClosest(int[] num, int target) {
        
        // Input validations
        // ...
        
        Arrays.sort(num);
        int len = num.length;

        int minDiff = Integer.MAX_VALUE;
        int result = 0;
        
        // Fix some int
        for (int i = 0 ; i < len ; i ++)
        {
            int m = i + 1;
            int n = len - 1;
            while (m < n)
            {
                int sum = num[i] + num[m] + num[n];
                if (sum == target)
                {
                    return sum; // A best result found.
                }
                else
                {
                    int diff = Math.abs(sum - target);
                    if (diff < minDiff)
                    {
                        minDiff = diff;
                        result = sum;
                    }    

                    if (sum > target)
                        n --;
                    else
                        m ++;
                }
            }
        }
        
        return result;
    }
}