Yeah, I had a look at python solutions and if I ignore the solutions that trivialize the kata with builtins, incorrect solutions are common.

It's a beginner kata, it should catch beginner mistakes, and this task makes it easy to create a slightly wrong solution that naive random tests don't catch.

I suggest adding these 75 exhaustive size-4 fixed tests to all languages (gotta love how each language has its own code):

import itertools

def rename(xs):
    # my implementation is probably smooth-brained
    keys = itertools.count(1)
    known = {}
    out = []
    for x, i in sorted((x, i) for i, x in enumerate(xs)):
        if x not in known:
            known[x] = next(keys)
        out.append((known[x], i))
    return tuple(x for (x, i) in sorted(out, key=lambda xi: xi[1]))

size = 4
xs = list(map(list, set(itertools.chain(*map(itertools.permutations, set(map(rename, itertools.combinations_with_replacement(range(1, size+1), size))))))))
print(xs)
print(len(xs))

[[1, 1, 1, 1], [1, 1, 1, 2], [1, 1, 2, 1], [1, 1, 2, 2],
 [1, 1, 2, 3], [1, 1, 3, 2], [1, 2, 1, 1], [1, 2, 1, 2],
 [1, 2, 1, 3], [1, 2, 2, 1], [1, 2, 2, 2], [1, 2, 2, 3],
 [1, 2, 3, 1], [1, 2, 3, 2], [1, 2, 3, 3], [1, 2, 3, 4],
 [1, 2, 4, 3], [1, 3, 1, 2], [1, 3, 2, 1], [1, 3, 2, 2],
 [1, 3, 2, 3], [1, 3, 2, 4], [1, 3, 3, 2], [1, 3, 4, 2],
 [1, 4, 2, 3], [1, 4, 3, 2], [2, 1, 1, 1], [2, 1, 1, 2],
 [2, 1, 1, 3], [2, 1, 2, 1], [2, 1, 2, 2], [2, 1, 2, 3],
 [2, 1, 3, 1], [2, 1, 3, 2], [2, 1, 3, 3], [2, 1, 3, 4],
 [2, 1, 4, 3], [2, 2, 1, 1], [2, 2, 1, 2], [2, 2, 1, 3],
 [2, 2, 2, 1], [2, 2, 3, 1], [2, 3, 1, 1], [2, 3, 1, 2],
 [2, 3, 1, 3], [2, 3, 1, 4], [2, 3, 2, 1], [2, 3, 3, 1],
 [2, 3, 4, 1], [2, 4, 1, 3], [2, 4, 3, 1], [3, 1, 1, 2],
 [3, 1, 2, 1], [3, 1, 2, 2], [3, 1, 2, 3], [3, 1, 2, 4],
 [3, 1, 3, 2], [3, 1, 4, 2], [3, 2, 1, 1], [3, 2, 1, 2],
 [3, 2, 1, 3], [3, 2, 1, 4], [3, 2, 2, 1], [3, 2, 3, 1],
 [3, 2, 4, 1], [3, 3, 1, 2], [3, 3, 2, 1], [3, 4, 1, 2],
 [3, 4, 2, 1], [4, 1, 2, 3], [4, 1, 3, 2], [4, 2, 1, 3],
 [4, 2, 3, 1], [4, 3, 1, 2], [4, 3, 2, 1]]

(maybe they need to be renamed again so the answer isn't always either 2 or 3)

size-5 lists might have some limited value too, there are 541 of those though.

This test was really well done. Gave me a good mental workout and really made me have to think about how to get the logic to work.

lol, i really struggled to understand the instructions (my bad, im dumb) which made this a lot harder than it should have. learned some new things too! I like.

Less padding in the description please. It's nice to know, but maybe after the question.

Approved by Johan

calling the parameter "sperm" 🤣🤣

Use the numbers stated in the kata's description. Where did you get that 0.354 factor? Not a kata issue.

Doesn't work for random values in Python.
For example, for mpg 8540, my solution gives 3023.16. It fails saying the right answer should be 3023.21.
Why this is failing?

Haskell translation

• you have an extraneous end at the end of your program which makes it ill-formed
• you need to return the function that you wrote and which solves the kata at the end of your program. currently, you are returning an empty table solution that you created, hence why the tests cannot run properly

Poorly written- the way it is worded and calling the parameter "sperm" suggests the argument is going to be "X" or "Y". It should be rewritten to make it clear that we are evaluating the chromosome pairs

--it should be ++it; the reverse_iterator is already going backwards

check for XY and XX only