Leetcode/Bloomberg -- 16. 3Sum Closest(3 ptr)

16. 3Sum Closest (3 ptr)
medium
https://leetcode.com/problems/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).

思路： like 3 sum，closes means calculate abs diffrenence, default res is sum of first 3 elements

public class Solution {
    public int threeSumClosest(int[] nums, int target) {
        Arrays.sort(nums);
        int res = nums[0] + nums[1] + nums[nums.length - 1];
        for(int i = 0; i+2 < nums.length; i++){
            int j = i+1, k = nums.length - 1;
            while(j < k){
                int sum = nums[i] + nums[j] + nums[k];
                if (sum > target){
                    k--;
                }else{
                    j++;
                }
                if (Math.abs(sum - target) < Math.abs(res - target)) {
                    res = sum;
                }
            }
        }
        return res;
    }
}