A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
Given a string s
, return true
if it is a palindrome, or false
otherwise.
Example 1:
Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: "amanaplanacanalpanama" is a palindrome.
Example 2:
Input: s = "race a car"
Output: false
Explanation: "raceacar" is not a palindrome.
Example 3:
Input: s = " "
Output: true
Explanation: s is an empty string "" after removing non-alphanumeric characters.
Since an empty string reads the same forward and backward, it is a palindrome.
Constraints:
-
1 <= s.length <= 2 * 105
-
s
consists only of printable ASCII characters.
SOLUTION:
class Solution:
def isPalindrome(self, s: str) -> bool:
s = "".join([c.lower() for c in s if c.isalnum()])
return s == s[::-1]
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