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"]

 class Solution:

     def reverseString(self, s):

         """

         :type s: List[str]

         :rtype: void Do not return anything, modify s in-place instead.

         """

         s[:]=s[::-1]

 if __name__=="__main__":

     s=Solution()

     list = [1,2,3]

     print(s.reverseString(list))

 class Solution:

     def reverseString(self, s):

         """

         :type s: List[str]

         :rtype: void Do not return anything, modify s in-place instead.

         """

         for i in range(len(s) // 2):

             temp = s[i]

             s[i] = s[-i - 1]

             s[-i - 1] = temp

 if __name__=="__main__":

     s=Solution()

     list = [1,2,3]

     print(s.reverseString(list))