344. 反转字符串
1、题目
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"]
提示：
1 <= s.length <=s[i]都是 ASCII 码表中的可打印字符
2、题解
题解1：直接交换
class Solution {public void reverseString(char[] s) {for(int i=0; i<(s.length)/2; i++) {char temp = s[i];s[i] = s[s.length-1-i];s[s.length-1-i] = temp;}System.out.println(s);}
}题解2：双指针交换
class Solution {public void reverseString(char[] s) {int i=0;int j=s.length-1;while(i<j) {char temp = s[i];s[i] = s[j];s[j] = temp;i++;j--;}System.out.println(s);}
}
