Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
For example,
"A
man, a plan, a canal: Panama"
is a palindrome.
"race
a car"
is not a palindrome.
Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.
For the purpose of this problem, we define empty string as valid palindrome.
? Solve this problem
去掉S中的无关字符,将大写字母转换为小写,之后就是简单的回文串判断。
原文:http://blog.csdn.net/u014082714/article/details/44308577