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#125. Valid Palindrome | LeetCode Python Solution

Problem​

LeetCode Problem

  1. Valid Palindrome

Python Solution​

We will implement a solution to check if a phrase is palindrome using a while loop with two pointers.

class Solution:
    def isPalindrome(self, s: str) -> bool:
        # Convert all uppercase letters to lowercase
        sLower = s.lower()

        # Remove all non-alphanumeric characters
        sAlphaNum = ""
        for ch in sLower:
            if ch.isalnum():
                sAlphaNum += ch

        # Check what we got so far
        print(sAlphaNum)

        # Check that it reads the same forward and backward using a while loop with two pointer technique
        startPtr, endPtr = 0, len(sAlphaNum)-1
        while endPtr > startPtr:
            # Return early as soon as a non-match is detected
            if sAlphaNum[startPtr] != sAlphaNum[endPtr]:
                return False

            startPtr += 1
            endPtr -= 1

        # If we get here, the phrase ia a palindrome
        return True