Can you solve the virus riddle? - Lisa Winer

譯者: Yueh-Lun Huang 審譯者: Amy H. Fann

Your research team has found a prehistoric virus

你的研究團隊 在永凍層發現了史前病毒

preserved in the permafrost

and isolated it for study.

並將它隔離研究

After a late night working,

深夜，在結束工作後

you're just closing up the lab when a sudden earthquake hits

你關上實驗室，一場突然的地震

and knocks out the power.

震斷了電源系統

As the emergency generators kick in, an alarm confirms your worst fears:

隨即，緊急電源啟動了

但警報聲通知你最害怕的事情：

all the sample vials have broken.

所有的試樣瓶已經碎裂

The virus is contained for now,

病毒仍在實驗室裡

but unless you can destroy it,

但是，除非你能摧毀它

the vents will soon open and unleash a deadly airborne plague.

通風口很快就會打開 在空氣中釋放致命的瘟疫

你沒有猶豫，穿起了化學防護衣

Without hesitation, you grab your HazMat suit

and get ready to save the world.

準備拯救世界

The lab is a four by four compound of 16 rooms

實驗室由四乘四，共十六間房間組成

with an entrance on the northwest corner and an exit at the southeast.

入口在西北角，出口則在東南角

Each room is connected to the adjacent ones by an airlock,

每個房間都有氣閘通往另一個房間

and the virus has been released in every room except the entrance.

除了入口那間，病毒已經擴散至 其他所有的房間

要摧毀它 你得進入每個被汙染的房間

To destroy it, you must enter each contaminated room

and pull its emergency self-destruct switch.

拉下緊急自毀開關

But there's a catch.

但是，有一個問題

Because the security system is on lockdown,

因為保安系統是上鎖的

once you enter the contaminated room,

一旦你進入被汙染的房間

you can't exit without activating the switch,

除非啟動開關，否則你無法離開

and once you've done so,

而且一旦啟動

you won't be able to go back in to that room.

你就無法再回到那個房間

You start to draw out possible routes on a pad of paper,

你開始在一沓紙張上繪製可能的路線

but nothing seems to get you to the exit

但似乎沒有辦法走到出口

without missing at least one room.

且不遺漏任何房間

So how can you destroy the virus in every contaminated room

所以，你要如何摧毀所有的病毒

and survive to tell the story?

並活下來講述這個故事呢？

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

如果你想自己找出答案 請先暫停一下

Answer in: 3

3

Answer in: 2

2

Answer in: 1

1

If your first instinct is to try to graph your possible moves on a grid,

如果你的第一反應是 繪製所有可能的路線

you've got the right idea.

你的想法是正確的

This puzzle is related to the Hamiltonian path problem

這個謎題關係到「哈密頓路徑問題」

named after the 19th century Irish mathematician William Rowan Hamilton.

以 19 世紀愛爾蘭數學家 哈密頓之名來命名

The challenge of the path problem

路徑問題的挑戰是找出

is to find whether a given graph has a Hamiltonian path.

一張特定的圖是否具有哈密頓路徑

That's a route that visits every point within it exactly once.

這條路線會經過所有的節點 且只經過一次

This type of problem, classified as NP-complete,

這類型的問題，被歸類在 「非決定性多項式完全」(NP-complete)

is notoriously difficult when the graph is sufficiently large.

當圖夠大時，它會變得非常困難

雖然，任何提出的路線 都可以被輕易地驗證

Although any proposed solution can be easily verified,

we have no reliable formula or shortcut for finding one,

我們卻沒有可靠的公式或捷徑 來找出正確的那條

or determining that one exists.

或確定它存在

And we're not even sure if it's possible for computers

我們甚至不知道

電腦是否能可靠地找出解決方案

to reliably find such solutions, either.

This puzzle adds a twist to the Hamiltonian path problem

這道謎題在哈米頓路徑問題上 增加了變化

in that you have to start and end at specific points.

你必須由特定的起點前往特定的終點

But before you waste a ton of graph paper,

但在你浪費大量的方格紙前

you should know that a true Hamiltonian path

你要知道，真正的哈密頓路徑

isn't possible with these end points.

是不可能連接這些端點的

That's because the rooms form a grid with an even number of rooms on each side.

因為房間所形成的網格 每邊都為偶數個房間

In any grid with that configuration,

任何這種配置的網格

a Hamiltonian path that starts and ends in opposite corners is impossible.

哈密頓路徑是不可能 從相對的角落開始並結束

Here's one way of understanding why.

原因如下

Consider a checkerboard grid with an even number of squares on each side.

想像一個正方的棋盤，每邊有偶數格

Every path through it will alternate black and white.

任一條路徑皆交替地經過黑格及白格

These grids will all also have an even total number of squares

這些正方網格，總共也是偶數個

because an even number times and even number is even.

因為偶數乘偶數仍為偶數

So a Hamiltonian path on an even-sided grid that starts on black

所以，哈密頓路徑在偶數邊的網格

會從黑格開始，並結束在白格

will have to end on white.

And one that starts on white will have to end on black.

而從白格開始，則會在黑格結束

However, in any grid with even numbered sides,

然而，在任何偶數邊的網格中

opposite corners are the same color,

相對的角都是相同的顏色

so it's impossible to start and end a Hamiltonian path on opposite corners.

所以哈密頓路徑不可能 在相對的角落開始並結束

It seems like you're out of luck,

看似是你不走運了

unless you look at the rules carefully and notice an important exception.

除非，你有仔細看過規則 且注意到一個例外

It's true that once you activate the switch in a contaminated room,

一旦你在受汙染的房間啟動開關

it's destroyed and you can never go back.

病毒會被摧毀，且你不可能回去

But there's one room that wasn't contaminated - the entrance.

但是，有一間未受汙染的房間

入口的那一間

This means that you can leave it once without pulling the switch

這意味你不需要拉開關就能離開房間

and return there when you've destroyed either of these two rooms.

並在摧毀相鄰的其中一間後回來

The corner room may have been contaminated

角落的房間可能會 在你開啟氣閘時受到汙染

from the airlock opening, but that's okay

但沒有關係

because you can destroy the entrance after your second visit.

因為你可以在第二次進入時 摧毀入口的那一間

That return trip gives you four options for a successful route,

這個返程能提供你四條成功路線

and a similar set of options if you destroyed this room first.

如果你先摧毀這間 也會有四條成功路線

Congratulations. You've prevented an epidemic of apocalyptic proportions,

恭喜，你阻止末日瘟疫了

but after such a stressful episode, you need a break.

在這緊張的事件後，你需要休息一會

Maybe you should take up that recent job offer to become a traveling salesman.

也許你該接受最近那份 旅行推銷員的工作邀約了