Well, exactly this is the case when &Vec<Vec<>> is better. I've started with

type Matrix = Vec<Vec<i32>>;

but then decided not to overcomplicate the code. We have a matrix type here, represented with Vec<Vec<>>, not an arbitrary slice of Vecs.

Also, there's nothing wrong with negatives in matrix, they should be allowed, but I don't see any actual reason to test them.

Added better diagnostic messages.

Fixed the incorrect function definition in solution setup.

this is now untrue, isomorphism is available :) https://www.codewars.com/kata/isomorphism

Should be marked as resolved

fixed

Yeah, I wanted to avoid overflow, but that didn't work. Thanks for catching that.

I've tried your suggestion, but b ended up as 0 or 1 in most cases.

I've also added assertion messages.

Fix

• Add random tests
• Add assertion messages
• Add language specific block in description

Thank you for reviewing that.

Approved

true but then you'd need two separate cases as opposed to one

You can get closer to a 50/50 split without much complexity by either one (or both) of these two means:

1. Do not use the same range of lengths for both hashmaps. Skew recipe towards having a smaller length and available towards having a larger length. Most translations don't use the same process to generate both from what I've seen.
2. Generate available after generating recipe. This allows you to subsequently specify that, say 50% of the time, you merge all the keys (ingredients) of recipe into whatever you got from INGREDIENTS.choose_multiple before collecting to a dictionary. I don't know if this is convenient in Rust, but it was easy to do in C#.

So far the chance of not getting a 0 is 4-5%; I think you should at least incorporate the first approach since most translations do it and it helps even the odds a bit.

Done and done. Pass by value makes it easier for the consumer, but by reference is the better api decision, and at this kata level they can handle it.

Ingredient diversity and count have been reduced for random tests. It's still likely to be mostly 0s, but before there was a decent chance they'd all be 0s. A more nuanced approach would be possible, but require complexity beyond what I think is necessary.

Would this be an okay asserion message?

Left - actual result, right - expected result. Test failed on string: "{case_str}"

<3

Wow! Thank you for that review and recommendations!