# Leetcode 125 - Valid panlidrome

Thoughts: Using double pointers shoud be my intuition. The trick part is to realize that I should avoid using

while loop inside the main while loop. For example, s = .,. Using while loop to increase i or j will lead to undefined error.

Notes: isNaN(parseInt(num)) is a good way to check if a string is purely numeric.

Quesiton:

Given a string s, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

Example 1:

Example 2: