Comparing two collections for equality irrespective of the order of items in them

Question

I would like to compare two collections (in C#), but I\'m not sure of the best way to implement this efficiently.

I\'ve read the other thread about Enumerable.Sequen

Answer 1

static bool SetsContainSameElements(IEnumerable set1, IEnumerable set2) {
    var setXOR = new HashSet(set1);
    setXOR.SymmetricExceptWith(set2);
    return (setXOR.Count == 0);
}

Solution requires .NET 3.5 and the System.Collections.Generic namespace. According to Microsoft, SymmetricExceptWith is an O(n + m) operation, with n representing the number of elements in the first set and m representing the number of elements in the second. You could always add an equality comparer to this function if necessary.