LeetCode.125.Valid Palindrome

原题链接：Valid Palindrome

题目内容：
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.

判断一个字符串是否是回文字符串，忽略标点

---

Python

class Solution(object):
    def isPalindrome(self, s):
        """
        :type s: str
        :rtype: bool
        """
        s = s.strip()
        if not s:
            return True
        if len(s) == 1:
            return True
        i = 0
        length = len(s)
        j = length - 1
        while i < length/2 + 1:
            if s[i].isalnum() and s[j].isalnum():
                if s[i].lower() == s[j].lower():
                    i += 1
                    j -= 1
                    continue
                else:
                    return False
            if not s[i].isalnum():
                i += 1
            if not s[j].isalnum():
                j -= 1
        return True

• 注意空串，” “，”.”这样的测试用例