wow, I never thought of using spaceship operator. Nicely done

Well, that's after I changed this:

    begin
      s1, s2 = two_sum(arr.dup, target)
    rescue NameError
      s1, s2 = twoSum(arr.dup, target)
    end

For this:

    if defined?(two_sum)
      s1, s2 = two_sum(arr.dup, target)
    else
      s1, s2 = twoSum(arr.dup, target)
    end 

Any idea why the first one gave that error instead of the out of bounds? I mean, hiding the real problem.

main.rb:14:in `block (2 levels) in two_sum': undefined method `+' for nil:NilClass (NoMethodError)
	from main.rb:12:in `loop'
	from main.rb:12:in `block in two_sum'
	from main.rb:11:in `loop'
	from main.rb:11:in `two_sum'

As it says, one of the arguments of the + inside the inner loop is nil, which means the index is out of bounds.

I saw it, but still I have no idea why that happens, sorry. Maybe someone who's more fluent in Ruby could find out why.

Hi Chrono79. I pasted the the solution that passes about 10 tests before getting that weird NoMethod error above if you want to replicate. Thank you :-)

I'm gonna explain why that happens (I hope), but that part of the code should run only if your function isn't called two_sum.

    begin
      s1, s2 = two_sum(arr.dup, target)
    rescue NameError
      s1, s2 = twoSum(arr.dup, target)
    end

And it's there for compatibility reasons. The Ruby translation used camelCase instead of snake_case at first and then that was changed. No idea why it would pass some tests and fail randomly. It doesn't happen with my solution.

I got that twoSum error too with Ruby. I've printed it out below. Mine passed about 8 tests before failing this one.

main.rb:37:in rescue in block (2 levels) in <main>': undefined method twoSum' for main:Object (NoMethodError)
Did you mean? two_sum

Part of me wonders if a test has twoSum as one of the method calls most likely me that's made the mistake though :-)

What language?

Thanks for this. Really enjoyed it. It was tricky to work out intially how to solve it. Loved the many different solution types people had. Great.

Oh wow. Such a creative way of solving this. Very nice indeed.
It took a while until I realised the alphabet was extended. I'll definitely steal this :-)

Wow I love this solution. So simple, concise and clear.