Palindrome (C#) : Algorithm

Write a function that checks if a given sentence is a palindrome. A palindrome is a word, phrase, verse, or sentence that reads the same backward or forward. Only the order of English alphabet letters (A-Z and a-z) should be considered, other characters should be ignored.

For example, IsPalindrome("Noel sees Leon.") should return true as spaces, period, and case should be ignored resulting with "noelseesleon" which is a palindrome since it reads same backward and forward.

Code Snippet

1. using System;
2. using System.Linq;
3. using System.Text.RegularExpressions;
4. public class Palindrome
5. {
6.     public static bool IsPalindrome(string str)
7.     {
8.         string tmpStr = str.ToLower().Trim();
9.         tmpStr = Regex.Replace(tmpStr, @"[^a-zA-Z]+", "");  //Replace all the special characters
10.         return tmpStr.SequenceEqual(tmpStr.Reverse());
11.     }
12.  
13.     public static void Main(string[] args)
14.     {
15.  
16.         Console.WriteLine(IsPalindrome("Noel sees Leon."));
17.     }
18. }