# How do I force-quit the program?

My friend has been playing with a program he found. He enters a 5-digit number into the command line and receives another 5-digit number in return. However, after 20 or so entries, he's about done and ready to quit. Unfortunately, there doesn't appear to be a "Quit" or "Exit" button anywhere in sight. These are his inputs and the program's responses thus far:

> 32908
Response: 32837
> 30351
Response: 32910
> 32872
Response: 32872
> 30280
Response: 30354
> 30278
Response: 32874
> 14727
Response: 30246
> 30246
Response: 32838
> 31992
Response: 14767
> 32799
Response: 31992
> 14654
Response: 30283
> 32944
Response: 14802
> 32909
Response: 32909
> 30316
Response: 32944
> 30354
Response: 30354
> 35536
Response: 35504
> 35538
Response: 32946
> 34276
Response: 26468
> 14619
Response: 35503
> 14875
Response: 34098
> 26533
Response: 26432
> ?????


Being a Linux expert, I know that every command-line program like this has a force-quit option, but I can't figure out how the program works. What should I tell my friend to type in place of the question marks in order to quit the program?

I'll add some clarification points to make this puzzle a bit more clear, since it (not surprisingly) has been causing some confusion!

• The story is mostly flavor, so I wouldn't stress too much over it. What you need to know are the entries and responses of the program, and the fact that my friend is trying to 'force-quit' it, whatever that might entail.
• A non-5 digit number probably would end up being an invalid input, though I might have to check that to be sure. Either way, that's not the solution to the puzzle. There is a valid input that will force the program to quit.
• This puzzle will require some knowledge that deems it unsolvable to a subset of the puzzlers on this site. If you're working hard on it and get stopped at that point, I encourage you to post a partial answer so that you can at least get some upvotes!
• The title may be confusing, but I promise that when the solution is revealed it will make perfect sense.
• There is a logical answer to this puzzle, but figuring out how to get there will involve some lateral thinking. I'm fixing the tags around right now and will add a related hint.

Hopefully this specifies everything for you. If you're still confused (which I wouldn't blame you for), here's a hint as well!

Hint 1:

The order in which you'll need to use the tags is: , , , . This could definitely be considered open to interpretation, but if you start with you'll be on the right track.

Hint 2:

There hasn't been much headway on this, so I might have made it a bit too cryptic... time will tell. Anyhow, it should at least be apparent that the 5-digit numbers do not represent actual 5-digit numbers. Try decrypting them in some fashion and see if the result looks like anything you've seen before. Even if it doesn't, posting your results might help other people get to the bottom of it. The encryption method used is not a difficult one.

Hint 3:

The given numbers are base 10. What do they look like in other bases?

Hint 4 (a biggish one):

My friend is playing some kind of game with the computer.

• He tried all of these. The program refuses to quit without proper input. :( – Bailey M Jul 2 '15 at 17:31
• CTRL-D? CTRL-C? Is this a real program, or a program made up for the puzzle? I have a hard time believing that none of these exit the program. – Ian MacDonald Jul 2 '15 at 17:45
• This is a totally made-up program in a totally made-up situation. I'm sure in a real program unplugging the computer would suffice to shut it down. – Bailey M Jul 2 '15 at 17:47
• @BaileyM: Was hoping you'd stick to your guns and insist that the computer was unplugged all along! Cue spooky music – Curmudgeon Jul 2 '15 at 17:57
• I'm theorizing that there is a mathematical/logical process that, when given the right input, will result in an illegal operation (divide by zero, for instance), thus crashing the program. – Aaron P Jul 2 '15 at 19:12

Expressing the numbers in

base 36

and

mapping the digits 10 through 35 to the letters A-Z

results in the following:

1. e4 c5
2. Nf3 e6
3. d4 cxd4
4. Nxd4 Nf6
5. Nd2 d6
6. Bd3 Nc6
7. Nxc6 bxc6
8. O-O Be7
9. b3 O-O
10. Bb2 Nd7
11. f4 Bf6
12. e5 dxe5
13. Ne4 exf4
14. Nxf6+ Nxf6
15. Rxf4 Re8
16. Rxf6 gxf6
17. Qg4+ Kf8
18. Ba3+ Re7
19. Bxh7 Qb6+?
20. Kh1 Ke8

It looks like your friend is

playing chess with the computer.

and needs to input

A move that checkmates the computer.

You can inspect the current state of the game here. It looks like our best move is

21. Rd1

Which forces

21. ... Qd4
22. Rxd4 e5
23. Qg8#

Converting back to numbers, the sequence is:

> 35461
response: 34168
> 35464
response: 32909
> 34280
bailey@puzzling~/chess\$ _

• You're correct that my friend needs to input a game config unwinnable by the computer, but you've gone the wrong direction in terms of base conversion. – Bailey M Jul 14 '15 at 15:27
• @Bailey Thanks for the hint... now I see why cryptograms makes sense. – 2012rcampion Jul 14 '15 at 15:38
• No problem! I realize I might have made this puzzle too difficult, but I'm eager for it to be solved because I rather like the solution. :) Hopefully I can help someone get there soon. EDIT: Hey, looks like you made the first jump! Well done. – Bailey M Jul 14 '15 at 15:43
• The values give perfect 4 digit numbers in Hex, which leads me to believe that's the right number base. I don't think chess can be interpreted this way though. > 808c 8045 768f 808e 8068 8068 7648 7692 7646 806a 3987 7626 7626 8046 7cf8 39af 801f 7cf8 393e 764b 80b0 39d2 808d 808d 766c 80b0 7692 7692 8ad0 8ab0 8ad2 80b2 85e4 6764 391b 8aaf 3a1b 8532 67a5 6740 – GettnDer Jul 14 '15 at 16:02
• @Gettn You may want to read up on standard notation and look at my answer again. – 2012rcampion Jul 14 '15 at 16:13

Try:

44444

Because

Fours quit the program

• Nice bit of wordplay! But it seems way too simple, and also doesn't justify the use of all those tags. – Rand al'Thor Jul 7 '15 at 10:05
• +1 for the humor although I agree it's unlikely to be the solution unless OP has created quite the school of red herrings. – Engineer Toast Jul 7 '15 at 12:08
• +1 for a clever answer, but I promise I haven't included any crazy red herrings. :) – Bailey M Jul 7 '15 at 13:34

I think that you should tell to him to try:

26432

Because:

All of the digits converted to hexadecimal are of type int16 (16 bits long, a.k.a unicode characters) and those characters are in the range of chinese and japanese characters, so every character have a meaning, like the last response of the program that is the unicode character "26432" (U+6740, 杀) that means "kill".

• WOW! That's really cool and not at all what I intended, but you're on the right track, I promise. :) – Bailey M Jul 10 '15 at 23:24

@2012rcampion is definitely on the right track. In fact, the winning move is:

21. Rd1 (as white)

The game is actually a recorded game between

Viacheslav Ragozin vs P Noskov

Here's a link to the game:

Again, full credit should go to @2012rcampion. I'm just a chess enthusiast doing some research :D

• Welcome to Puzzling! – GentlePurpleRain Jul 14 '15 at 17:23
• 2012rcampion gets the correct answer badge for his work plus providing the correct answer as well, but +1 for linking to the exact game I was referencing! Welcome to puzzling as well :) – Bailey M Jul 14 '15 at 17:26

Try:

Ctrl + C

Because:

that force-quits a program in Mac, Linux and Windows ;)

• You obviously haven't been reading the comments underneath the question. This computer's been possessed, and the program won't quit, even if you pull out the plug. – mmking Jul 10 '15 at 14:34