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[leetcode]3Sum Closest

2024-07-11 22:29:03   220人阅读

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：
这道题跟[leetcode]3Sum并没有太大差别，甚至比更简单，因为并不需要再关心重复数组了，只需要维护一个最小值即可。

代码如下：
public class Solution {    public int threeSumClosest(int[] num, int target) {        int length = num.length;        int min = Integer.MAX_VALUE;        int result = 0;        Arrays.sort(num);        for(int i = 0; i < length - 2;i++){            int begin = i + 1;            int end = length - 1;            while(begin < end){                if(Math.abs(num[i] + num[begin] + num[end] - target) < min){                    min = Math.abs(num[i] + num[begin] + num[end] - target);                    result = num[i] + num[begin] + num[end];                }                if(num[i] + num[begin] + num[end] > target) end--;                else if(num[i] + num[begin] + num[end] < target) begin++;                else return target;            }        }        return result;    }}

　还是要记得排序，求和问题中，排序似乎是很有效的。　


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