LeetCode 125. Valid Palindrome

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题目

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

Note: For the purpose of this problem, we define empty string as valid palindrome.

Example 1:

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Input: "A man, a plan, a canal: Panama"
Output: true

Example 2:

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Input: "race a car"
Output: false

Constraints:

  • s consists only of printable ASCII characters.

思路

Easy.

代码

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class Solution(object):
    def isPalindrome(self, s):
        """
        :type s: str
        :rtype: bool
        """
        isValid = lambda x : x == x[::-1]
        string = ''.join([x for x in s.lower() if x.isalnum()])
        return isValid(string)