The Furnace Bots | Think Like A Coder, Ep 3

譯者: Clement Fu 審譯者: 潘 可儿

[TED-Ed 原創系列]

《時代女神 x 程式邏輯革命》

[地點：八達圍]

[第三集：佔「零」]

Ethic and her robot Hedge agree to help the resistance leader, Adila,

焚燒文藝的黑魔熔爐獸已橫行無忌

sabotage the art-incinerating furnace-bots.

彥霖和機器人凌杰要仗義擊潰惡黨

In exchange,

巾幗之約

Adila promises to lead them to the first object of Ethic’s quest,

光復領袖艾德拉為救世雙俠當明燈

an artifact called the Node of Power.

指引到第一枚瑰寶：力量之泉

Years ago, there was just one furnace-bot.

想當年，只有一隻熔爐獸

It had a 0 inside its furnace and an unknown,

熔爐內刻有 0，序號是未知的亂數

randomly generated serial number.

Over time, the original self-replicated to produce more identical furnace-bots.

時移世易，零母自我複製出相同個體

Each child inherited the original’s unknown serial number within its furnace,

子體在熔爐中繼承本體的未知序號

and had a random, unique serial number of its own inscribed on its shell.

外殼上則刻有自己獨特的隨機序號

The second generation of furnace- bots also self-replicated in the same way,

第二代鐵甲暴龍同樣如斯繁衍

always passing their own serial numbers to their offspring’s furnaces.

將自己的序號傳到後代的熔爐中

This continued on for many generations.

生生不息

Today, each furnace-bot receives its orders from its parent.

每只暴龍如今都對母體唯命是從

So if Ethic can find the original 0 bot and somehow change its instructions,

倘若彥霖找到零母始祖改變指令

she could take over the entire army, all at once.

就能一舉拿下整支黑魔兵團

Adila has the perfect solution:

艾德拉有一個無懈可擊的辦法

a data crystal that she’s been carrying for years,

多年來她隨身收藏一枚資料水晶

waiting for the right moment to activate it.

就看準時機用在一時

It contains a program designed to gain control of a bot

水晶有一個程式能掌控鐵甲魔獸

and give it new instructions.

重新對牠發號施令

But if it’s uploaded to any furnace- bot other than the original,

不過若上傳到始祖以外的鐵甲暴龍

the 0 bot will override the instructions

零母就會覆寫指示

and destroy the data crystal in the process.

並一併摧毀資料水晶

The feeding is just a few minutes away,

迫在眉睫的炊事日

and there’s only one chance to get this right.

就是押注成敗的千載一時

Fortunately, Hedge’s ability to store data can help.

幸好凌杰儲存資料的能力派上用場

In programming,

程式設計中

a piece of information gets stored in something called a variable.

一闋資訊能儲存到一個「變數」：

Variables are basically containers that hold onto numbers, words, or other values.

即數字、文字或其他數值的載體

How does Ethic program Hedge to find the original 0 bot as quickly as possible?

彥霖如何指令凌杰才儘快找到零母？

Pause now to figure it out for yourself.

[動腦筋就按暫停，倒數五下給祕訣]

Here’s a hint.

祕訣：

Programs can be written to have as many variables as you need,

編寫程式變數多寡，隨心所欲無上限

but you can solve this problem with just one.

但這道題用一個變數就行

Hedge can use it to store a serial number

凌杰可反覆用一個變數來儲存序號

and replace it with a new one as often as he needs.

需要時就換上新的序號

Pause now to figure it out for yourself.

[動腦筋就按暫停，倒數五下揭謎底]

A key insight here is that Hedge doesn’t need to map out the entire

重點是凌杰不須比對出整個族譜

set of relationships to find the original furnace-bot.

才能找到零母始祖

If, for example, he gets lucky and picks the original one right away,

若幸運之神眷顧一挑就挑到零母

he’ll be done.

就功德圓滿

But if he starts with any other bot,

挑上其他暴龍的話

he can still find a path that leads straight back to the 0-bot

順藤摸瓜總能尋回零母

by following a simple set of instructions.

只需跟隨簡單的指令集

To help craft them, let’s first simplify the problem.

先簡化一下問題，編指令沒難度

Let’s say there were only three furnace-bots;

舉例說現在只有三只暴龍

a parent and two children, but you don’t know which is which.

一母兩子，哪只是哪只分不清楚

You could have Hedge pick one at random and look inside its furnace.

就叫凌杰隨意挑一個窺探一下熔爐

Now, you know the family tree looks like this.

族譜是這樣子已說在前頭

If the number inside the furnace is a 0, you’ve found the parent.

熔爐中的數字若是 0，就找到母體

If not, then no matter which child you chose,

不然，無論挑哪一個子體

it must have the parent’s serial number in its furnace.

熔爐內都找到母體的序號

So in this scenario, you’re guaranteed to find the parent in one or two moves.

範例中找到母體只消一、兩下功夫

In actuality, there are many furnace-bots,

回歸現實，鐵甲暴龍多不勝數

and you don’t know how many generations there are

不知道已繁衍至多少代

nor what the family tree looks like.

族譜當然也不得而知

But you don’t need to,

但上述都不重要

because Hedge can just keep repeating the same sequence of actions

凌杰只消重覆一組相同的套路

until he gets to the original.

直至找到零母始祖為止

How? With a loop.

方法？就是用迴圈

Hedge can pick any bot at random, look inside its furnace,

凌杰隨意挑一只暴龍窺探一下熔爐

and store that serial number as a variable.

把熔爐內的序號儲存在一個變數

Then he’ll begin the following loop that will repeat

之後就重覆一個迴圈

until the stored variable equals 0,

直到儲存的變數等於 0 為止

the furnace number of the original bot:

即是迴圈找到零母始祖就完成：

1. Find the bot whose shell serial number matches the stored number.

一、找出外殼序號脗合變數的暴龍

2. Look inside its furnace.

二、查看暴龍的熔爐

3. Store that new number, overwriting the old one.

三、記下數字，變數換成新序號

Once the loop ends, we’ll know that Hedge has found the 0 bot,

迴圈告終時，即代表凌杰找到零母

so he should upload the control program.

就可以把掌控程式上傳

So here’s what happens:

言歸正傳

Hedge only takes 5 repetitions to find the original:

凌杰只消五下功夫便找到零母：

robot 733 has the 0 in its furnace.

暴龍編號 733 熔爐內正刻著 0

In a blink of a mechanical eye,

倏忽之間，程式就在兵團中傳開

the program spreads through the entire army, and Adila takes control.

落入艾德拉掌控

She has the furnace-bots give off theatrical bouts of flame

她令暴龍施放煙幕特效的火之幻術

to hide the fact that they’re now secretly safe-guarding

暗度陳倉保守吞噬的文藝著作

all of that artistic output.

Now that Ethic’s delivered the furnace-bots,

彥霖功成交付馴服的熔爐獸團

Adila honors her end of the deal.

艾德拉也信守巾幗之約

She leads Ethic and Hedge to the location of the first artifact,

為彥霖凌杰引路到第一枚瑰寶：

the Node of Power.

力量之泉

There, one thing is immediately clear:

現場形勢擺在眼前

they’ll have to steal it.

出奇制勝唯靠神偷