Check Palindrome by Filtering Non-Letters

Origin: Check Palindrome by Filtering Non-Letters

Given a string containing letters, digits, and symbols, determine if it reads the same forwards and backwards when considering only alphabetic characters (case-insensitive).

Example

Input

code = A1b2B!a

Output

1

Explanation

- Step 1: Extract only letters → ['A','b','B','a'] 
- Step 2: Convert to lowercase → ['a','b','b','a'] 
- Step 3: Compare sequence forward and backward: 'abba' == 'abba' → true

Input Format

• A string code containing letters (A–Z, a–z), digits (0–9), and symbols

Constraints

• 0 ⇐ code.length ⇐ 1000
• For all 0 ⇐ i < code.length: 33 ⇐ ASCII(code[i]) ⇐ 126
• code contains only printable ASCII characters (letters, digits, symbols)

Output Format

• Return a boolean value: 1 if true & 0 if false. Sample Input 0

Z

Sample Output 0

1

Sample Input 1

abc123cba

Sample Output 1

1

Resolution

function isAlphabeticPalindrome(code: string): boolean {
  // Write your code here
  if (!code)
    return false;
  const arr = code
    .toLocaleLowerCase()
    .split('')
    .filter(s => /[a-z]/i.test(s));
  const reArr = [...arr].reverse();
  // const reArr = arr.toReversed(); es2023+
  return reArr.join() === arr.join();
}