LeetCode 0016

原题链接：

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

题意理解

首先我们是做过3sum的，于是显然，我们有一个$O(n^2)$ 的做法

我的代码

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int closest = nums[0] + nums[1] + nums[2];
        int diff = Math.abs(target - closest);
        Arrays.sort(nums);
        for (int i = 0; i < nums.length - 2; i++) {
            int l = i + 1;
            int r = nums.length - 1;
            while (l < r) {
                int sum = nums[i] + nums[l] + nums[r];
                int newDiff = Math.abs(target - sum);
                if (newDiff < diff) {
                    diff = newDiff;
                    closest = sum;
                }
                if (sum < target) {
                    l++;
                } else {
                    r--;
                }
            }
        }
        return closest;
    }
}