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 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"]

解题思路

class Solution:
    def reverseString(self, s: [str]) -> None:
        """
        Do not return anything, modify s in-place instead.
        """
        #交叉替换
        # midNum = len(s)//2
        # for i in range(midNum):
        #     s[i], s[len(s)-1-i] = s[len(s)-1-i], s[i]
        #python内置函数
        s.reverse()