125-valid-palindrome

125. Valid Palindrome (Easy) (https://leetcode.com/problems/valid-palindrome/)

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string s, return true if it is a palindrome, or false otherwise. Constraints: - 1 <= s.length <= 2 * 10^5 - s consists only of printable ASCII characters.

function isPalindrome(s: string): boolean {
  const lc = s.toLocaleLowerCase().replace(/[^a-zA-Z\d]/g, "");
  return lc === lc.split("").reverse().join("");
}
 
// function isPalindrome(s: string): boolean {
//   const lc = s.toLowerCase().replace(/[^a-z0-9]/g, "");
//   let i = 0,
//     j = lc.length - 1;
//   while (i < j) {
//     if (lc[i] !== lc[j]) return false;
//     i++;
//     j--;
//   }
//   return true;
// }
 
// Local check:
console.log(isPalindrome("A man, a plan, a canal: Panama"));
console.log(isPalindrome("race a car"));
console.log(isPalindrome(" "));

Example 1:
 
    Input: s = "A man, a plan, a canal: Panama"
    Output: true
    Explanation: "amanaplanacanalpanama" is a palindrome.
 
  Example 2:
 
    Input: s = "race a car"
    Output: false
    Explanation: "raceacar" is not a palindrome.
 
  Example 3:
 
    Input: s = " "
    Output: true
    Explanation: s is an empty string "" after removing non-alphanumeric characters.
    Since an empty string reads the same forward and backward, it is a palindrome.

two-pointers 151-reverse-words-in-a-string та же задача через RegExp leetcode