题目:

本题验证字符串s是否为回文串，在验证之前，我们首先要去掉s中包含的空格和标点符号，何以用一下代码来去除:

        c=""English="1234567890abcdefghijklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM"for j in s:if j in English:c+=jc=c.lower()

去除之后得到了新的字符串c,我们可以用Python中自带的索引切片[::-1]来简单的判断是否为回文串：

class Solution:def isPalindrome(self, s: str) -> bool:i=0c=""English="1234567890abcdefghijklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM"for j in s:if j in English:c+=jc=c.lower()if c==c[::-1]:return Trueelse:return False

也可以自己写出一个算法（我是根据len(c)是否为偶数来分别讨论的。）:

class Solution:def isPalindrome(self, s: str) -> bool:i=0c=""English="1234567890abcdefghijklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM"for j in s:if j in English:c+=jc=c.lower()if len(c)==1 or len(c)==0:return Trueelif len(c)==2:if c[0]==c[1]:return Truereturn Falseelif len(c)==3:if c[0]==c[2]:return Truereturn Falseif len(c)%2==0:while i<=int(len(c)/2-1):if c[i]==c[len(c)-1-i]:i+=1else:return Falsereturn Trueelse:while i<=int((len(c)-1)/2-1):if c[i]==c[len(c)-1-i]:i+=1else:return Falsereturn True