Question

For example a string contains the following (the string is variable):

http://www.google.comhttp://www.google.com

What would be the most efficient way of removing the duplicate url here – e.g. output would be:

http://www.google.com 

Answer 1

Efficiency has various definitions: code size, total execution time, CPU usage, space usage, time to write the code, etc. If you want to be “efficient”, you should know which one of these you’re trying for.

I’d do something like this:

string url = "http://www.google.comhttp://www.google.com";
if (url.Length % 2 == 0)
{
    string secondHalf = url.Substring(url.Length / 2);
    if (url.StartsWith(secondHalf))
    {
        url = secondHalf;
    }
}

Depending on the kinds of duplicates you need to remove, this may or may not work for you.