Not an issue, your code is wrong.

Hint: You said I've tried 10000centuries as mention above, how many years are there in the 10,000th century?

Also, The expression (centuryFromYear(year)) == (expected) is false. is not an issue, it is part of codewars. Try returning a wrong value for Multiply in C (in case it is what you meant).

@salten .. Well ..

• Thanks Bro for notifying me ..
• but please , in what language did your try solving the kata .. I'm tuned to know bro .. regards .. Zizou

This error stems from vectors having only 1 element or empty vectors. In that case numbers[1] has no meaning.