Can you solve the rogue AI riddle? – Dan Finkel

Can you solve the rogue AI riddle? – Dan Finkel


A hostile artificial intelligence called
NIM has taken over the world’s computers. You’re the only person skilled
enough to shut it down, and you’ll only have one chance. You’ve broken into NIM’s secret lab, and now you’re floating in a raft on top
of 25 stories of electrified water. You’ve rigged up a remote
that can lower the water level by ejecting it from grates
in the sides of the room. If you can lower the water level to 0, you can hit the manual override, shut NIM off, and save the day. However, the AI knows that you’re here,
and it can lower the water level, too, by sucking it through a trapdoor
at the bottom of the lab. If NIM is the one to lower
the water level to 0, you’ll be sucked out of the lab, resulting in a failed mission. Control over water drainage
alternates between you and NIM, and neither can skip a turn. Each of you can lower the water level
by exactly 1, 3, or 4 stories at a time. Whoever gets the level
exactly to 0 on their turn will win this deadly duel. Note that neither of you can lower
the water below 0; if the water level is at 2, then the only move is to lower
the water level 1 story. You know that NIM has already computed
all possible outcomes of the contest, and will play in a way that maximizes
its chance of success. You go first. How can you survive
and shut off the artificial intelligence? Pause here if you want
to figure it out for yourself. Answer in: 3 Answer in: 2 Answer in: 1 You can’t leave anything up to chance –
NIM will take any advantage it can get. And you’ll need to have a response
to any possible move it makes. The trick here is to start from where
you want to end and work backwards. You want to be the one to lower
the water level to 0, which means you need the water level
to be at 1, 3, or 4 when control switches to you. If the water level were at 2, your only option would be
to lower it 1 story, which would lead
to NIM making the winning move. If we color code the water levels, we can see a simple principle at play: there are “losing” levels like 2, where no matter what whoever starts
their turn there does, they’ll lose. And there are winning levels,
where whoever starts their turn there can either win or leave their opponent
with a losing level. So not only are 1, 3,
and 4 winning levels, but so are 5 and 6, since you can send your opponent
to 2 from there. What about 7? From 7, all possible moves would
send your opponent to a winning level, making this another losing level. And we can continue up
the lab in this way. If you start your turn 1, 3,
or 4 levels above a losing level, then you’re at a winning level. Otherwise, you’re destined to lose. You could continue like this
all the way to level 25. But as a shortcut, you might notice that levels 8 through 11
are colored identically to 1 through 4. Since a level’s color is determined by
the levels 1, 3, and 4 stories below it, this means that level 12
will be the same color as level 5, 13 will match 6, 14 will match 7, and so on, In particular, the losing levels
will always be multiple of 7, and two greater than multiples of 7. Now, from your original
starting level of 25, you have to make sure your opponent starts
on a losing level every single turn— if NIM starts on a winning level
even once, it’s game over for you. So your only choice on turn 1
is to lower the water level by 4 stories. No matter what the AI does, you can continue giving it losing levels until you reach 0
and trigger the manual override. And with that, the crisis is averted. Now, back to a less stressful
kind of surfing.

100 thoughts on “Can you solve the rogue AI riddle? – Dan Finkel

  1. Sign up for free to be emailed the solution to the bonus riddle: https://brilliant.org/teded! Also, the first 833 of you who sign up for a PREMIUM subscription will get 20% off the annual fee. Now go solve some riddles!

  2. Bonus Answer.
    Let's find losing moves.
    And I will name chocolate pieces like this;
    123
    456(4=poisoned)
    Losing moves are;
    4(obviously)
    145
    12456
    Which means you can simply eat chocolate 3.

  3. Bonus riddle:
    Ted Ed: You and a friend are eating chocolate and the bottom right is poison
    Me: I'm allergic so ALL OF IT IS POISON

  4. I have this idea: we call the total number of floors that Nim and we can take in two turns, x (x> = 5, x of N *), we know that in 4 turns we and Nim can go> = 20. because 4 is an even number, so if Nim starts then we will end up having 26 floors all counting the zero floor. I reversed that we will go on the 0th floor and end the 26th floor so if we are on the 24th floor we will win (24th floor is 2nd floor) but 24-20 = 4 so if Nim starts on 3rd floor ie 21st floor, Nim loses so we just need to go down 25-21 = 4 floors in the first turn.

  5. This "take a turn at drainage" thing is extremely effective, especially since that it is actually possible to beat it.

  6. Why does NIM even have a manual override button? Also you could just jump off the raft when NIM lowers the water level to 0.

  7. For the bonus riddle, the answer is top middle. That will leave 1 square above and two squares to the right. Your opponent would be forced to eat one of these, while you can eat the other, leaving only the poison square

  8. “The AI knows all move possible” – Said TedEd while completely explaining how to defeat the AI easily

  9. I love how the AI is named after the classic game of NIM with the same concept just under different terms 🖤 it’s almost impossible to beat NIM in his own game without cheating though…

  10. Taking a stab at the bonus riddle, is it the single top right corner square? I say this because if you choose that then the only square left for the next player to choose is the square under it, so you could repeat this until they have to choose the death square

  11. Or…you could just…yknow…call in an A-10 wathog and blast holes into the thing until the water drains. Or just call in a nuke, same effect

  12. on bonus riddle..
    i will eat the two on the op so my opponents move is to eat two chocolate or one but if he eat 2 i will eat the 1 so he will die.. when he eat 1 chocolate only i will eat two so he didnt have choice he will die again and again 😂😂

  13. For the last one: Just don't eat the corner.

    If you are an odd number, so you will always win.

    If you are an even number, you'd always loose.

  14. For the candy bar the right two first, then your opponent can either do two squares or one, you pick the last two or one, he dies.

  15. Me: wears hazmat suit with oxygen tank
    Now I can swim and hit the button. Too easy.
    Also, NIM clearly built this chamber. Why not add turrets at the top?

  16. That chocolate bar brings me some memories… Also there's a non constructive proof that for any tablet that is a rectangle (or square) the first player can have a winning strategy, you just don't know which one. In this case, eating only the first top right square guarantees that the first player can win, as far as I can see

  17. "You're the only person skilled enough to shut it down"
    about 10 seconds later: pushes button and shuts down AI
    me: now that's skill right there

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