Palindrome Checker

StringTwo Pointers

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward as forward, ignoring punctuation, case, and spacing.

Example 1

Input

[
  "A man a plan a canal Panama"
]

Output

true

Explanation. After removing all non-alphanumeric characters, and converting to lowercase, 'amanaplanacanalpanama' is a palindrome.

Example 2

Input

[
  "race a car"
]

Output

false

Explanation. After proper formatting, 'raceacar' is not a palindrome.

Example 3

Input

[
  " "
]

Output

true

Explanation. An empty string or a string composed only of whitespace is considered a palindrome.

Example 4

Input

[
  "0P"
]

Output

false

Explanation. After considering alphanumeric characters and ignoring cases, '0p' is not a palindrome.

Follow-up: How would you handle strings with special characters or emojis?

Constraints:

The input string may contain letters (both uppercase and lowercase) and numeric characters.

Views: 2