Question

This is a code example from solution. I’m looking for the way to eliminate Problem classes repeated. I was watching Contains method in List.

public IEnumerable<Problem> Create(int quantify)
{
    for (int i = 0; i < quantify; i++)
    {
        yield return Create();
    }
}

Answer 1

If you simply want to eliminate any duplicates and Problem supports equality then use the Distinct method.

IEnumerable<Problem> collection = ...;
IEnumerable<Problem> noRepeats = collection.Distinct();