125. Valid Palindrome Solution

Author: doh6077

valid-palindrome/doh6077.py

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+import re
+# two pointers 
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        # remove all alphanumeric characters and convert all uppercase letters into lowercase letters
+        cleaned_s = re.sub(r'[^a-zA-Z0-9]', '', s).lower()
+        n = len(cleaned_s)
+        left, right = 0, n -1
+        while left < right: 
+            if cleaned_s[left] == cleaned_s[right]:
+                left += 1 
+                right -= 1
+            else:
+                return False 
+        
+        return True