best

The very same for me. Didn't thought putting last element as 0! Smart!.

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[18.0, 19.0, 59.0] should equal [18, 20, 0]

No random tests.

TypeError: 'int' object is not iterable ???

I like dictionaries!

IMHO this isn't an issue. The description is global for every language and should be an information, that you can use a dict specified in the selected language.

For that case, there is an info in the description:

Every letter has to start with an increasing index.. "ONENO" results to 11, because the E can be used two times. Endless loops are not possible!

111 wouldn't be possible, since the index is increasing and the strings "ONE", "NEN" and "ENO" would be used.

recover("ONENO") => "11"
why not 111?

I just wonder is there any real reason for ; then eventhough then on next line do same trick?

the code is not efficient, takes long time to finish
try a way to get rid of the while loop

https://docs.python.org/3/tutorial/datastructures.html#comparing-sequences-and-other-types

Man that's perfect

Exactly what I did :P, the trick was making the last key 0 in the dictionary for the modulo to work for any nb_petals being a multiple of 6 :P