Valid Palindrome

validPalindrome.js

/**
 * @param {string} s
 * @return {boolean}
 */
var isPalindrome = function(s) {
    const regex = /[^a-z0-9]/gmi;
    s = s.replace(regex, "").toLowerCase();
    
    let l = 0; 
    let r = s.length - 1;
    while(l <= r) {
        if(s[l] === s[r]) {
            l++;
            r--;
        } else {
            return false;
        }
    }

    return true;
};

// Convert the given string to desired form using regex and replace
// Run a while loop with 2 pointers, one pointing at the start and the other at the end of the string
// If the value at both pointers is same, increase the start pointer and decrease the end pointer till they meet at the middle
// If at any place the values are not same, return false
// Else return true

// Time: O(n)
// Space: O(1)