/**
 * 
 * Ashish Patel
 * e: ashishsushilPatel@gmail.com
 * w: https://ashish.me
 *
 */

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

Note: For the purpose of this problem, we define empty string as valid palindrome.

Example 1:

Input: "A man, a plan, a canal: Panama"
Output: true
Example 2:

Input: "race a car"
Output: false
 */

function validPalindrome(value) {
  const str = value.replace(/[^0-9a-z]/gi, '').toLowerCase(); 
  let left = 0;
  let right = str.length - 1;
  while(left < right){
    if(str[left] !== str[right]){
      return false
    }
    left += 1
    right -= 1
  }
  return true
}

test('valid Palindrome', () => {
  expect(validPalindrome('A man, a plan, a canal: Panama')).toEqual(true)
  expect(validPalindrome('race a car')).toEqual(false)
});