CODE

public class Solution {
  public bool IsPalindrome(string s) {

    s = s.Trim();
    s = s.ToLower();
    s = Regex.Replace(s, "[^a-z0-9]", String.Empty);

    int start = 0;
    int end = s.Length - 1;
    while (start < end)
    {
      if (s[start] != s[end])
        return false;
      start++;
      end--;
    }        
    return true;
  }
}