cool

I totally agree with Matteo. The only reason why I wasted my time with this problem is to be able to properly complain about such a loss of time.
It is not about English not being your mother tongue though. English is not my mother tongue neither and I can give complete and non contradictory instructions.
The instructions doesn't specify why the value of the old car matters (you have to understand from the examples you can sell it in order to buy the new one). The explanation about the float rounding is contradictory. It tells you to truncate and to aproximate it to the nearest int in the same phrase. It is a disaster.

I improved the Kotlin assertion messages. The problem should be clearer now.

What if the block lambda inside forceRun throws an Error? The program should continue

Interpreting instructions in a real-world application is not always easy either. I like to think of these as practice for dense or unclear legacy code or hard to read documentation. It is also often the case that the author's first language is not English, in which case I'm sure a suggestion for clearer instruction would be helpful

in the last line itemIndex / itemsPerPage shouldn't we be inc it by 1?
Very neat solution by the way.

Parenthesis are unnecessary since && has higher precedence than ||

It should be added to the description

Without leading zeros. k is 2 for d=3.

I really do not understand Let k be the number of bits of d

For example the decimal number 3 can be converted to the binary number:

• 11 (k = 2)
• 0011 (k = 4)
• 00000011 (k = 8)
• and so on

Kotlin:

My solution works well in Intellij but here it gives me an exception:

expected: kotlin.collections.EmptyList<[]> but was: java.util.Collections$SingletonList<[]>

I really don't understand

old kata, other ranking scale as nowadays, yada yada yada .. enjoy the easy points !

Definitely not a 4 kyu kata

How to make the oper function accepts only methods of Opstrings?