c# - Filter out path strings beginning with strings

Question

I have a collection of paths (e.g. C:Users, C:Userscheese, D:Shadowstuff ,D:Shadow). Is there any way to get rid of strings that are lesser path? e.g. to only leave C:Userscheese and D:Shadowstuff and make it FAST and memory un-intensive?

It is important that the strings can come in any order.

Answer 1

I would order paths in descending way, and then just skip sub-paths when enumerating collection of paths and adding them to results:

string[] paths = { @"C:Users", @"C:Userscheese", @"D:Shadowstuff", @"D:Shadow" };

string currentPath = "";
List<string> result = new List<string>();
var comparer = StringComparer.InvariantCultureIgnoreCase;

foreach (var path in paths.OrderByDescending(p => p, comparer))
{
    if (currentPath.IndexOf(path, StringComparison.InvariantCultureIgnoreCase) >= 0)
        continue;

    result.Add(path);
    currentPath = path;
}

Result:

[
  "D:\Shadow\stuff",
  "C:\Users\cheese"
]