Computer Science Foyer Puzzle #41

Previous puzzles: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17)
(18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29)
(30) (31) (32) (33) (34) (35)
(36) (37) (38) (39) (40)


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What is the correct answer?

It is up to you to figure out!

How do I make sure that the answer I come up with is correct?

As soon as you find the correct answer, you'll just know it. It is a unique feeling you can't mistake for anything else.

Can you please tell me the correct answer?

You see, a puzzle is like a tiny box with a present. The "present" contained in it is not the solution, no. Instead, it is the unique feeling of satisfaction you will experience when you solve the puzzle. By finding the answer from someone else you are destroying the present and depriving yourself of the opportunity to experience this unique feeling. Moreover, by coming up with a solution you will develop your analytic abilities — it is that feeling of satisfaction which actually helps to wire your neurons. Consequently, we strongly oppose the whole idea of giving away the answer. We hope you will understand it and come to appreciate it.

We also ask you not to spoil the fun for others and keep the answers to yourself after you find them.

But what if I can't find the answer on my own?

Then the puzzle will stay unsolved for you this time. Maybe you'll try solving it later. Maybe the answer will accidentally pop in your head while you are doing something different (a unique experience in itself!). Even if you never find out the answer, there is really nothing wrong with that! It's still better than spoiling it. The world is full of unsolved puzzles.

Who posted this puzzle? How can I contact him?

So far puzzles are suggested by Konstantin. Mail him at

I know an awesome puzzle!

Great! Send your ideas to (Don't send solutions!)