Question

I have a linq query for project euler problem 243:

var y = from n in factors
        from m in factors where m != n
        select n * m;

The problem is, for prime factors 2 and 3, it produces the y = {6, 6} where it needs to just be {6}.

Is there a way to do this without calling y.Distinct() or y.Contains() multiple times?

I also thought about using two foreach loops, but the problem is – I can’t use indexing so it’d just be cumbersome and awkward.

Answer 1

As stated by Rick Sladkey, changing

    from m in factors where m != n

to

    from m in factors where m < n

produces the correct result without having to use .Distinct().