Valid-Palindrome

Author: Shikha-code36

Strings/isvalidPalindrome.py

@@ -20,3 +20,6 @@ def isPalindrome(self, s):
         return True
     else:
         return False
+
+#T:O(N)
+#S:O(N)

Two-pointers/validpalindrome.py

@@ -0,0 +1,30 @@
+"Leetcode - https://leetcode.com/problems/valid-palindrome/"
+'''
+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.
+'''
+def isPalindrome(self, s: str) -> bool:
+        i=0
+        j=len(s)-1
+        
+        while i<j:
+            while i<j and not s[i].isalnum():
+                i+=1
+            while i<j and not s[j].isalnum():
+                j-=1
+            if s[i].lower() != s[j].lower():
+                return False
+            
+            i+=1
+            j-=1
+        return True
+        
+#T:O(N)
+#S:O(1)