LeetCode 344. 反转字符串---村雨遥

题目344. 反转字符串[1]描述

编写一个函数，其作用是将输入的字符串反转过来。输入字符串以字符数组 char[] 的形式给出。

不要给另外的数组分配额外的空间，你必须**原地[2]修改输入数组**、使用 O(1) 的额外空间解决这一问题。

你可以假设数组中的所有字符都是 ASCII[3] 码表中的可打印字符。

示例 1：

输入：["h","e","l","l","o"]输出：["o","l","l","e","h"]

示例 2：

输入：["H","a","n","n","a","h"]输出：["h","a","n","n","a","H"]

解题思路若数组长度为偶数，则遍历数组长度的一半；若数组长度为奇数，则遍历数组长度的一半向下取整；然后定义一个临时变量，用临时变量将字符数组前后元素交换位置；实现package string; import java.util.Arrays; /** * Created with IntelliJ IDEA. * Version : 1.0 * Author : cunyu * Email : cunyu1024@foxmail.com * Website : https://cunyu1943.github.io * Date : 2020/3/19 22:35 * Project : LeetCode * Package : string * Class : ThreeHundredFortyFour * Desc : 344.反转字符串 */ public class ThreeHundredFortyFour { public static void main(String[] args) { ThreeHundredFortyFour threeHundredFortyFour = new ThreeHundredFortyFour(); char[] s = {'1', '3', '9', '7'}; threeHundredFortyFour.reverseString(s); System.out.println(Arrays.toString(s)); } /** * 反转字符串 * @param s */ public void reverseString(char[] s) { for (int i = 0; i < (int) (s.length / 2); i++) { char tmp = s[i]; s[i] = s[s.length - 1 - i]; s[s.length - 1 - i] = tmp; } } }参考资料

[1]

344. 反转字符串: https://leetcode-cn.com/problems/reverse-string/

[2]

原地: https://baike.baidu.com/item/原地算法

[3]

ASCII: https://baike.baidu.com/item/ASCII

---来自腾讯云社区的---村雨遥