C#: how do you check lists are the same size & same elements?

Question

There are two lists of string

List A;
List B;

What is the shortest code you would suggest to check that A.Count ==

Answer 1

If you don't need to worry about duplicates:

bool equal = new HashSet(A).SetEquals(B);

If you are concerned about duplicates, that becomes slightly more awkward. This will work, but it's relatively slow:

bool equal = A.OrderBy(x => x).SequenceEquals(B.OrderBy(x => x));

Of course you can make both options more efficient by checking the count first, which is a simple expression. For example:

bool equal = (A.Count == B.Count) && new HashSet(A).SetEquals(B);

... but you asked for the shortest code :)