Java [leetcode 16] 3Sum Closest

標籤：

題目描述：

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).

解題思路：

這個跟3Sum的思路差不多，不過實現的過程就簡單多了。外面一個大的迴圈，裡面也是從兩邊開始，如果三個數之和減去目標值的絕對值較小，則更新之並記錄此三個數之和。

代碼如下：

 1 public class Solution { 2     public int threeSumClosest(int[] nums, int target) { 3         int length = nums.length; 4         int min = Integer.MAX_VALUE; 5         int left, right, comp, result = 0; 6  7         if (length < 3) 8             return 0; 9         Arrays.sort(nums);10 11         for (int i = 0; i < length - 2; i++) {12             left = i + 1;13             right = length - 1;14             while (left < right) {15                 comp = nums[i] + nums[left] + nums[right];16                 if (Math.abs(comp - target) < min){17                     min = Math.abs(comp - target);18                     result = comp;19                 }20                 if (comp > target)21                     right--;22                 else if (comp < target)23                     left++;24                 else25                     return target;26             }27         }28         return result;29     }30 }

 

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).

Java [leetcode 16] 3Sum Closest