(LeetCode)Valid Palindrome --- 判断回文字符串

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.

解题分析：

    此题目的解题思路就是先去掉不必要的字符，空格等，在根据二分方法，判断回文字符串。

# -*- coding:utf-8 -*-__author__ = 'jiuzhang'class Solution(object):    def isPalindrome(self, s):        new_s = []        for c in s:            if c.isalnum():                new_s.append(c.lower())        length = len(new_s)        for i in range(length/2):            if new_s[i] != new_s[length - i - 1]:                return False        return True<span style="color:#c7254e;"></span>