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 s 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。
示例 1：
输入：s = ["h","e","l","l","o"] 输出：["o","l","l","e","h"]
示例 2：
输入：s = ["H","a","n","n","a","h"] 输出：["h","a","n","n","a","H"]
1.直接进行交换
class Solution { public void reverseString(char[] s) { int length=s.length; for(int i=0;i<length/2;i++){//判断要循环的次数 char temp=s[i]; s[i]=s[length-1-i];//头尾间要交换的数字 s[length-1-i]=temp; } } }
