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.
class Solution:
def isPalindrome(self, s):
"""
:type s: str
:rtype: bool
"""
s = ("".join([a for a in s if a.isalpha() or a.isdigit()])).lower()
left = 0
right = len(s) - 1
while left < right:
if s[left] != s[right]:
return False
left += 1
right -= 1
return True
class Solution:
def isPalindrome(self, s):
"""
:type s: str
:rtype: bool
"""
s = ("".join([a for a in s if a.isalpha() or a.isdigit()])).lower()
return s == s[::-1]
