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病毒之谜 – 译学馆
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病毒之谜

Can you solve the virus riddle? - Lisa Winer

你的调查小组发现一种史前病毒
Your research team has founda prehistoric virus
被保存到永久冻土里 被隔离开以便研究
preserved in the permafrost and isolated it for study.
工作到半夜之后
After a late night working,
你正关上实验室的时候 突然地震了
you’re just closing up the lab when a sudden earthquake hits
电路都跳了
and knocks out the power.
当应急发动机开始工作时
As the emergency generators kick in,
警报证实了你最担心的事情:
an alarm confirms your worst fears:
所有样品瓶都碎了
all the sample vials have broken.
目前 病毒被控制在房间里
The virus is contained for now,
但是除非你能毁掉它
but unless you can destroy it,
不然 气孔不久会打开并释放出这种致命的 能在空气中传播的瘟疫
the vents will soon open and unleash a deadly airborne plague.
你不假思索的抓起你的防护衣
Without hesitation, you grabyour HazMat suit
准备好要拯救世界
and get ready to save the world.
实验室是由4 x 4分布的16个房间组成
The lab is a four by four compoundof 16 rooms
西北角有个入口 出口在东南
with an entrance on the northwest corner and an exit at the southeast.
每个房间通过气闸与相邻房间连接
Each room is connected to the adjacentones by an airlock,
并且病毒弥漫于除入口处房间外的所有房间
and the virus has been released in every room except the entrance.
为了摧毁病毒 你必须进入每个受污染的房间
To destroy it, you must enter eachcontaminated room
并拉下应急自毁开关
and pull its emergencyself-destruct switch.
但是有个条件
But there’s a catch.
因为安全系统已经锁死
Because the security systemis on lockdown,
一旦你进入被污染的房间
once you enter the contaminated room,
你不激活开关是出不去的
you can’t exit withoutactivating the switch,
一旦你激活了开关
and once you’ve done so,
你就不能再返回之前的房间
you won’t be able to go back in to that room.
你开始着手在纸上
You start to draw out possible routes
画出可能的路线
on a pad of paper,
但是看起来没有一条路线是可以在不遗漏任何房间的情况下
but nothing seems to get youto the exit
到达出口的
without missing at least one room.
那么 你怎样才能在每个被污染的房间消灭病毒
So how can you destroy the virusin every contaminated room
并活着来讲述这个故事呢?
and survive to tell the story?
如果你想自己找出答案 那么请在这里暂停
Pause here if you wantto figure it out for yourself.
答案揭晓倒计时 3
Answer in: 3
2
Answer in: 2
1
Answer in: 1
如果你第一反应是
If your first instinct is to try to
尝试在格子上画出行走路线
graph your possible moves on a grid,
那么你的主意是对的
you’ve got the right idea.
这个谜题与哈密顿回路问题有关
This puzzle is related tothe Hamiltonian path problem
这是由19世纪爱尔兰数学家威廉•罗文•哈密顿的名字命名的
named after the 19th century Irishmathematician William Rowan Hamilton.
路线问题的难点是
The challenge of the path problem is to find
找出给定的图案是否有哈密顿回路
whether a given graph has a Hamiltonian path.
即路线经过每个点有且仅有一次
That’s a route that visitsevery point within it exactly once.
这类问题被归为NP-complete结构
This type of problem, classifiedas NP-complete,
当图案足够大时 该问题会相当的难
is notoriously difficult when the graphis sufficiently large.
尽管任何方案都能很容易被证实
Although any proposed solutioncan be easily verified,
但我们没有可靠的公式和捷径找出解决路线
we have no reliable formula or shortcutfor finding one,
或确定是否这条路线存在
or determining that one exists.
而且我们甚至不确定计算机是否能
And we’re not even sureif it’s possible for computers
找到这种解决办法
to reliably findsuch solutions, either.
这个谜题还在哈密顿回路问题基础上拐了个弯
This puzzle adds a twistto the Hamiltonian path problem
你必须要在指定的点上开始和结束
in that you have to startand end at specific points.
但在你浪费大量方格纸之前
But before you waste a ton of graph paper,
你应该知道 真正的哈密顿回路
you should know that a trueHamiltonian path
在满足这些起始点的情况下 是不可能的
isn’t possible with these end points.
那是因为该房间的网格
That’s because the rooms form a grid
每一边的房间数都是偶数
with an even number of rooms on each side.
这样配置的任何网格
In any grid with that configuration,
起点和终点位于对角的哈密顿回路是不可能的
a Hamiltonian path that starts and ends in opposite corners is impossible.
这儿有个理解其原因的方法
Here’s one way of understanding why.
想一下每边的方格数都是偶数的西洋象棋盘网格
Consider a checkerboard grid with an even number of squares on each side.
每个通过方格的路径都会在黑与白间变换
Every path through it will alternateblack and white.
这些网格
These grids will all also have
的方格总数也是偶数
an even total number of squares
因为偶数与偶数相乘还是偶数
because an even number timesand even number is even.
所以在一个四边都是偶数的网格里
So a Hamiltonian path
哈密顿回路是从黑到白
on an even-sided grid that starts on black will have to end on white.
从白到黑
And one that starts on white will have to end on black.
然而 在边数为偶数的网格里
However ,in any grid with evennumbered sides,
相对的角是相同的颜色
opposite corners are the same color,
所以在哈密顿回路里 起点和终点是对角的话 是不可能的
so it’s impossible to start and end a Hamiltonian path on opposite corners.
看起来 你不太幸运啊
It seems like you’re out of luck,
除非你仔细查看规则 并注意到一条重要的例外
unless you look at the rules carefully and notice an important exception.
虽然一旦你在污染房间激活开关
It’s true that once you activate the switch in a contaminated room,
房间被毁 你不能回去了
it’s destroyed and you can never go back.
但是有一个房间没被污染 那就是入口
But there’s one roomthat wasn’t contaminated – the entrance.
那表示你可以在不激活它的情况下
This means that you can leave it once
再次经过
without pulling the switch
之后 当你已经毁掉了这两个房间的任意一个时 再回来
and return there when you’vedestroyed either of these two rooms.
角上的房间可能因为气闸开启已经被污染了
The corner room may havebeen contaminated
但是 没关系
from the airlock opening,but that’s okay
因为你可以在第二次到房间时毁掉入口
because you can destroy the entranceafter your second visit.
这种可返回的行程给你提供了四种成功的路线选择
That return trip gives you four optionsfor a successful route,
如果你先把这个房间毁了 那么也会有一组相似的路线选择恭喜你
and a similar set of options if you destroyed this room first. Congratulations.
你已经阻止了一场世界范围的传染病
You’ve preventedan epidemic of apocalyptic proportions,
但在这件紧张的事件之后 你需要休息下
but after such a stressful episode,you need a break.
或许你应该接受最近的工作机会 成为一名旅行推销员
Maybe you should take up that recent job offer to become a traveling salesman.

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哈密顿回路的逻辑问题

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翻译译者

lala

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审核员 V

视频来源

https://www.youtube.com/watch?v=ZKh6z0X6KRw

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