Can you solve the rogue AI riddle? - Dan Finkel

翻译人员: Sizhen Wang 校对人员: Sylvie Han

A hostile artificial intelligence called NIM has taken over the world’s computers.

一个邪恶的人工智能 NIM 控制了全世界的电脑。

You’re the only person skilled enough to shut it down,

你是唯一一个有能力关闭它的人，

and you’ll only have one chance.

且你只有一次机会。

You’ve broken into NIM’s secret lab,

你闯入了 NIM 的秘密实验室，

and now you’re floating in a raft on top of 25 stories of electrified water.

现在正坐在浮在 25 层高的 带电水上的一个皮筏艇里。

You’ve rigged up a remote that can lower the water level

你已装配了一个遥控器，

by ejecting it from grates in the sides of the room.

它可以通过把水从房间两侧的格子 排走来降低水位。

If you can lower the water level to 0,

如果你可以把水位降到 0，

you can hit the manual override,

你就可以按下手动操作按钮，

shut NIM off,

关闭 NIM

and save the day.

并拯救世界。

However, the AI knows that you’re here, and it can lower the water level, too,

但是这个 AI 知道你在这，

它也能通过用实验室底部的 活板门抽水，让水位降低。

by sucking it through a trapdoor at the bottom of the lab.

If NIM is the one to lower the water level to 0,

如果 NIM 把水位降低到了 0，

you’ll be sucked out of the lab,

你就会被吸出实验室，

resulting in a failed mission.

从而导致任务失败。

Control over water drainage alternates between you and NIM,

你和 NIM 轮流排水，

and neither can skip a turn.

谁也不可以跳过任何一轮。

Each of you can lower the water level by exactly 1,

你们俩每轮可以把水位降低刚好 1 层，

3,

3 层或 4 层。

or 4 stories at a time.

Whoever gets the level exactly to 0 on their turn

谁在轮到自己时把水位降到了 0

will win this deadly duel.

谁就是这生死之战的赢家。

Note that neither of you can lower the water below 0;

注意，你们俩谁都不能让 水位降到 0 以下；

if the water level is at 2,

假如水位在 2，

then the only move is to lower the water level 1 story.

那你们就一次只能让水位降 1 层。

You know that NIM has already computed all possible outcomes of the contest,

你知道 NIM 已经计算出了 这场比赛的所有可能结果，

and will play in a way that maximizes its chance of success.

而且它会选择以能让它自己 赢的可能性最大化的方式来玩。

You go first.

你先出招。

How can you survive and shut off the artificial intelligence?

你要怎样才可以存活下来 并终结这个人工智能呢？

Pause here if you want to figure it out for yourself.

如果你想自己想想的话， 请在这里暂停。

Answer in: 3

答案揭晓倒计时：3

Answer in: 2

答案揭晓倒计时：2

Answer in: 1

答案揭晓倒计时：1

You can’t leave anything up to chance - NIM will take any advantage it can get.

你不可以把任何一步交给命运—— NIM 会利用任何潜在优势。

And you’ll need to have a response to any possible move it makes.

你得准备好应对 NIM 所有招数的措施。

The trick here is to start from where you want to end and work backwards.

这里的技巧是从理想结局开始进行倒推。

You want to be the one to lower the water level to 0,

你想成为那个把水位降到 0 的人，

which means you need the water level to be at 1, 3, or 4

意味着你需要水位在轮到你时

when control switches to you.

在 1，3 或 4 的位置。

If the water level were at 2,

如果水位当时在 2 的位置，

your only option would be to lower it 1 story,

你唯一的选择便会是让水位降低 1 层，

which would lead to NIM making the winning move.

这就会让 NIM 获胜。

If we color code the water levels,

如果我们用颜色标记一下这些水位，

we can see a simple principle at play:

我们就会发现玩这个游戏的一个简单原则：

there are “losing” levels like 2,

游戏里存在一些“必输”层，比如第 2 层，

where no matter what whoever starts their turn there does, they’ll lose.

一旦轮到那一层，无论是谁都必输无疑。

And there are winning levels, where whoever starts their turn there

游戏里也存在一些必胜层， 无论是谁轮到那些层

can either win or leave their opponent with a losing level.

谁都能赢或是把他们的对手逼到必输层。

So not only are 1, 3, and 4 winning levels,

所以不只是 1，3 和 4是必胜层，

but so are 5 and 6,

5 和 6 也是，

since you can send your opponent to 2 from there.

因为从那些位置你可以 把你的对手送到第 2 层。

What about 7?

那么第 7 层是什么情况呢？

From 7, all possible moves would send your opponent to a winning level,

到了第 7 层，所有可能的移动 都会把你的对手送到必胜层，

making this another losing level.

所以这又是一个必输层。

And we can continue up the lab in this way.

我们可以继续这样往上推理。

If you start your turn 1, 3, or 4 levels above a losing level,

如果轮到你时你在一个必输层 上面 1，3 或 4 层的位置，

then you’re at a winning level.

那你就位于一个必胜层。

Otherwise, you’re destined to lose.

否则，你必输无疑。

You could continue like this all the way to level 25.

你可以像这样一路推理到第 25 层。

But as a shortcut,

不过还有一条捷径，

you might notice that levels 8 through 11 are colored identically to 1 through 4.

你可能注意到了，第 8 到 11 层和 第 1 到 4 层的颜色是一样的。

Since a level’s color is determined by the levels 1, 3, and 4 stories below it,

由于层级的颜色取决于 位于它下面 1，3 或 4 层的颜色，

this means that level 12 will be the same color as level 5,

所以第 12 层的颜色会和第 5 层的颜色一样，

13 will match 6,

13 会和 6 一样，

14 will match 7, and so on,

14 会和 7 一样，以此类推，

In particular, the losing levels will always be multiple of 7,

必输层的层数永远会是 7 的倍数，

and two greater than multiples of 7.

以及比 7 的倍数大 2 的数。

Now, from your original starting level of 25,

现在，从你的出发点 25 层起，

you have to make sure your opponent starts on a losing level every single turn—

你得确保你的对手在任何一局中 都位于必输层——

if NIM starts on a winning level even once,

因为一旦 NIM 处于必胜层，哪怕是一次，

it’s game over for you.

你就完了。

So your only choice on turn 1 is to lower the water level by 4 stories.

所以在第一轮时你唯一的选择 就是让水位降低 4 层。

No matter what the AI does,

这样无论 AI 怎么做，

you can continue giving it losing levels

你都可以把必输层推给它

until you reach 0 and trigger the manual override.

直到你到达第 0 层， 启动手动操作装置。

And with that, the crisis is averted.

这样危机就解除了。

Now, back to a less stressful kind of surfing.

现在，回到一种 更轻松的冲浪里吧（即上网）。