125-valid-palindrome.py

"""
Problem Link: https://leetcode.com/problems/valid-palindrome/

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:
Input: "A man, a plan, a canal: Panama"
Output: true
Example 2:

Input: "race a car"
Output: false
"""
classSolution:
defisPalindrome(self, s):
"""
 :type s: str
 :rtype: bool
 """
low,high=0 ,len(s)-1
whilelow<high:
whilelow<highandnots[low].isalnum():
low+=1
whilelow<highandnots[high].isalnum():
high-=1
ifs[low].lower() !=s[high].lower():
returnFalse
low+=1
high-=1
returnTrue