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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);}
}