Check if string is Palindrome in C#

using System;

using System.Collections.Generic;

using System.Linq;

class MainClass {

static void Main() {

Console.WriteLine($"For sentence 'Kayak' is: {CheckIfSentenceIsPalindrome("Kayak")}");

Console.WriteLine($"For sentence 'Kozak' is: {CheckIfSentenceIsPalindrome("Kozak")}");

Console.WriteLine($"For sentence 'To jest juz za dlugie' is: {CheckIfSentenceIsPalindrome("To jest juz za dlugie")}");

Console.WriteLine($"For sentence 'A man, a plan, a canal, Panama!' is: {CheckIfSentenceIsPalindrome("A man, a plan, a canal, Panama!")}");

Console.WriteLine($"For sentence 'Was it a car or a cat I saw?' is: {CheckIfSentenceIsPalindrome("Was it a car or a cat I saw?")}");

}

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

private static bool CheckIfSentenceIsPalindrome(string word){

if (word.Length < 1) return true;

int leftSideIndex = 0;

int rightSideIndex = word.Length-1;

while (leftSideIndex < rightSideIndex)

{

while (leftSideIndex < rightSideIndex && !Char.IsLetterOrDigit(word[leftSideIndex])) {

leftSideIndex++;

}

while (leftSideIndex < rightSideIndex && !Char.IsLetterOrDigit(word[rightSideIndex])) {

rightSideIndex--;

}

if (Char.ToLower(word[leftSideIndex]) != Char.ToLower(word[rightSideIndex])) return false;

leftSideIndex++;

rightSideIndex--;

}

return true;

}

}