344. 反转字符串(双指针)

/** * 344. 反转字符串 * @author wsq * @date 2020/10/08 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 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"] 链接：https://leetcode-cn.com/problems/reverse-string */ package com.wsq.sstring; public class ReverseString { /** * 双指针 * @param s */ public void reverseString(char[] s) { int n = s.length; if(n == 0){ return; } int left = 0; int right = n - 1; while(left < right){ if(s[left] != s[right]){ char tmp = s[left]; s[left] = s[right]; s[right] = tmp; } left++; right--; } } public static void main(String[] args) { char[] s = {'h','e','l','l','o'}; System.out.println("翻转前："); printCharArr(s); ReverseString rs = new ReverseString(); rs.reverseString(s); System.out.println("翻转后："); printCharArr(s); } public static void printCharArr(char[] arr) { for(char c: arr) { System.out.print(c + " "); } System.out.println(); } }