you are completely correct! many thanks for pointing this out. I have done some, uh, heavy refactoring, including adding your critical example to the test suite. ;)

that's a correct test. [0] (min) = 1, [1] (next smaller number not in the array) = 3, [2] (max) = 4

I'm not sure I follow you. The "solution" function does not assume unique numbers. It is designed to handle duplicates.