125 Verify palindrome string ✅¶

Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: "amanaplanacanalpanama" is a palindrome.

Input: s = "race a car"
Output: false
Explanation: "raceacar" is not a palindrome.

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace Algorithms.Simple
{
  public class Palindrome
  {
    public static bool IsPalindrome(string inputString)
    {

      if (String.IsNullOrEmpty(inputString))
      {
        return true;
      }

      var rg = new Regex(@"[^a-zA-Z0-9]");
      var charArray = rg.Replace(inputString.Trim(), String.Empty).ToLower();

      for (int i = 0, j = charArray.Length - 1; i < j; i++, j--)
      {
        if (charArray[i] != charArray[j])
        {
          return false;
        }
      }

      return true;
    }
  }
}

using Algorithms.Simple;
using Xunit;

namespace AlgorithmTests.Simple
{
  public class PalindromeTests
  {
    [Fact]
    public void EvaluateTrue()
    {
      Assert.True(Palindrome.IsPalindrome("A man, a plan, a canal: Panama"));
    }

    [Fact]
    public void EvaluateFalse1()
    {
      Assert.False(Palindrome.IsPalindrome("race a car"));
    }


    [Fact]
    public void EvaluateFalse2()
    {
      Assert.False(Palindrome.IsPalindrome("abb"));
    }
  }
}

/*
 * @lc app=leetcode id=125 lang=javascript
 *
 * [125] Valid Palindrome
 */
// Only handle English characters (the title ignores uppercase and lowercase, we converted all of them to lowercase, so here we only judge lowercase) and numbers
function isValid(c) {
  const charCode = c.charCodeAt(0);
  const isDigit =
    charCode >= '0'.charCodeAt(0) && charCode <= '9'.charCodeAt(0);
  const isChar = charCode >= 'a'.charCodeAt(0) && charCode <= 'z'.charCodeAt(0);

  return isDigit || isChar;
}
/**
 * @param {string} s
 * @return {boolean}
 */
var isPalindrome = function(s) {
  s = s.toLowerCase();
  let left = 0;
  let right = s.length - 1;

  while (left < right) {
    if (!isValid(s[left])) {
      left++;
      continue;
    }
    if (!isValid(s[right])) {
      right--;
      continue;
    }

    if (s[left] === s[right]) {
      left++;
      right--;
    } else {
      break;
    }
  }

  return right <= left;
};