Puzzle #4 - The min-max question

Here is a question you are bound to stumble upon in one of your logic design job interviews, why? I don’t know, I personally think it is pretty obvious, but what do I know…

MinMax2 is a component with 2 inputs - A and B, and 2 outputs - Max and Min. You guessed it, you connect the 2 n-bit numbers at the inputs and the component drives the Max output with the bigger of the two and the Min output with the smaller of the two.

Your job is to design a component - MinMax4, with 4 inputs and 4 outputs which sorts the 4 numbers using only MinMax2 components. Try to use as little as possible MinMax2 components.

If you made it so far, try making a MinMax6 component from MinMax2 and MinMax4 components.

For bonus points - how many different input sequences are needed to verify the logical behavior of MinMax4?