125.js

// https://leetcode.com/problems/valid-palindrome/description/
//
//
// 125. 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.
//
//
//
// 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.
//
//
// Constraints:
//
// 1 <= s.length <= 2 * 105
// s consists only of printable ASCII characters.
//
// /**
//  * @param {string} s
//  * @return {boolean}
//  */
// var isPalindrome = function(s) {
//
// };

/**
 * @param {string} s
 * @return {boolean}
 */
const isPalindrome = (s) => {
  const chars = s.toLowerCase().replace(/[^a-z0-9]/g, "");
  return chars === chars.split("").reverse().join("");
};

//test
isPalindrome("A man, a plan, a canal: Panama"); //true