Valid Palindrome

Given a string s, return true if it is a palindrome, otherwise return false. A palindrome is a string that reads the same forward and backward. It is also case-insensitive and ignores all non-alphanumeric characters. Note: Alphanumeric characters consist of letters (A-Z, a-z) and numbers (0-9).

After considering only alphanumerical characters we have "wasitacaroracatisaw", which is a palindrome.