The Prison Break | Think Like A Coder, Ep 1

譯者: Lilian Chiu 審譯者: Harper Chang

《用程式設計師的方式思考》

[ 位置：監獄 ]

[ 第一集：逃獄 ]

Upon emerging from stasis, Ethic is the unfortunate recipient of three surprises.

從深度睡眠中甦醒過來之後，

艾希克得到了三個不幸的「驚喜」。

The first: a prison cell.

第一：監獄牢房。

The second: complete amnesia.

第二：完全失憶。

And the third: a mysterious stranger has gotten stuck

第三：一個神祕陌生的東西想要

擠過她的窗戶鐵條之間卻卡住了。

squeezing through the bars on her window.

His name is Hedge, and he has come to help Ethic save the world.

他叫海吉， 來協助艾希克拯救世界。

But first they have to break out of jail.

但首先他們得要逃獄。

Hedge turns his hand into a lockpick and outlines the challenge ahead.

海吉把他的手變成開鎖工具， 並說明了他們要面臨的挑戰。

Each lock in the prison works in the same unusual way.

獄中的每個鎖都用了 同一種不尋常的設計。

Inside the keyhole is a red dial that can be rotated to one of 100 positions

在鑰匙孔中有一個紅色轉盤，

可以轉到一百個刻度的其中之一，

numbered 1 through 100.

編號一到一百。

The key for a given cell spins the dial to the right position,

每一間牢房的鑰匙能將 鎖的轉盤轉到正確的位置，

which, when stopped there, makes it turn green and unlocks the door.

轉盤的位置對了就會變成綠色， 接著門就會被解鎖。

It would be out of the question to steal keys from a guard,

從守衛身上偷鑰匙是不可能的，

but Hedge has a better idea.

但海吉有個更好的點子。

Hedge can carry out Ethic‘s commands.

海吉能執行艾希克的指令。

If Ethic tells him to walk 5 steps forward,

如果艾希克要他向前走五步、

turn right, then walk another 5 steps,

向右轉、再前進五步，

that’s exactly what he’ll do.

他就會完全照做。

Hedge needs specific instructions though.

不過海吉需要明確的指示。

If Ethic says “pick the lock” or “try every combination”

如果艾希克說「把鎖打開」 或「嘗試所有組合」，

that would be too vague, but “spin the dial 5 positions forward” would work.

那就太模糊了，

但說「把轉盤向前轉五格」 就是可行的。

Once out of the cell, they will only have a few moments to crack the lock

離開牢房之後，

他們只有一點時間 破解外面監獄大門的鎖，

for the outer prison door too before the guards catch them.

太慢就會被守衛逮到。

So what instructions will allow Hedge to efficiently open any door?

所以，什麼樣的指示能讓海吉 有效率地打開任何一扇門？

Pause now to figure it out for yourself.

請在這裡暫停，自己思考片刻。

Before we explain the solution, here’s a hint.

在解答之前，先提供一個提示。

A key programming concept that can help unlock the door is called a loop.

有一種寫程式的關鍵概念， 能夠協助將門解鎖，

那就是迴圈。

This can be one or more instructions that Hedge will iterate— or repeat—

也就是說，海吉能將一個或數個指示

迭代或重覆執行一定的次數，

a specified number of times,

like “jump up and down 100 times.”

比如「上下跳一百次」。

Or an instruction that Hedge will repeat until a condition is met,

或者海吉不斷重覆某個指示， 直到某個條件被滿足為止，

such as “keep jumping up and down until it’s 7 o’clock.”

比如「持續上下跳， 直到七點為止」。

Pause now to figure it out for yourself.

如果你想自己嘗試，請在此暫停。

The first thing that’s clear is that you need to find a way for Hedge

第一件事很明確， 就是要找出一種方法，

讓海吉去嘗試所有組合， 直到試出能開鎖的那一組。

to try every combination until one works.

What takes a little more effort is how exactly you do so.

比較要花心力的， 是要如何做到這件事。

One solution would be to instruct Hedge to try every combination in succession.

一種解決方案是讓海吉 去依序嘗試所有組合。

Try 1 and check the light.

嘗試 1，然後檢查 轉盤燈號的顏色。

If it turns green, open the door, and if not, try 2.

如果燈號變綠色，就打開門，

如果沒有變綠色，就嘗試 2。

If that doesn’t work try 3. All the way up to 100.

如果不行，再嘗試 3，

一直嘗試到 100。

But it would be tedious to lay that out in its entirety.

但這整個過程會非常冗長。

Why write more than 100 lines of code,

為什麼要寫超過一百行的程式，

when you can do the same thing with just 3?

如果只要用三行程式 就能做到同樣的事？

This is where a loop comes in.

這就是迴圈出場的時候了。

There are a few ways to go about this.

有幾種方法可以應用迴圈。

The lock has 100 positions,

鎖有一百個刻度，

so Ethic could say “Check the dial’s color, then spin the dial forward once,

所以，艾希克可以說：

「檢查轉盤的顏色，接著 將轉盤再向前轉一個刻度，

for 100 repetitions.

重覆一百次。

Remember where the dial turns green, then have Hedge set it back to that number.”

記住轉盤變成綠色時的數字，

讓海吉最後將它設回那個數字。」

A loop like this, where you specify the number of times it repeats,

像這樣指明重覆次數的迴圈，

is called a “for" loop.

稱為「for」迴圈。

But an even more efficient loop

但還有更有效率的迴圈，

would have Hedge spin the dial one position at a time until it turns green

就是要海吉將轉盤一次轉 一個刻度，直到它變成綠色，

and as soon as that happens, have him stop and open the door.

一旦變成綠色， 就要他停止並將門打開。

That way if the door unlocks on 1,

這麼一來，如果在 試到 1 時門就解鎖了，

he doesn’t need to cycle through all the rest of the numbers.

他就不用把其他數字都嘗試完。

This is an “until” loop,

這是「until」迴圈，

because it involves doing an action until a condition is met.

因為它的重點在於持續 執行一個動作，直到條件滿足。

A similar, alternate approach would be to turn the dial while it’s still red,

還有一個類似的替代方法：只要 轉盤還是紅色，就持續轉動它，

then stop.

否則停止。

That’s called a “while” loop.

叫做「while」迴圈。

Back to the adventure.

回到原本的冒險。

Hedge loops through the combinations, and the cell opens at 41.

海吉重覆嘗試不同組合，

在 41 時，牢房打開了。

Ethic and Hedge wait until the perfect moment in the guards’ rotation

艾希克和海吉等到 守衛繞行的完美空檔時機，

and make a break for it.

逃出牢房。

Soon, Ethic faces a choice: hide inside a mysterious crystal,

艾希克馬上就面臨了一個選擇：

躲在神秘的水晶當中，

or try to crack the outer door and make a run for it.

或嘗試破解外面的大門，逃出去。

Ethic chooses to run.

艾希克選擇逃出去。

The second door takes Hedge longer, requiring him to spin all the way to 93.

第二扇門讓海吉花了更多時間，

一直嘗試到 93 才解鎖。

But he gets it open

但他把門打開了。

and takes the opportunity to explain why he’s rescued Ethic.

海吉用這個機會，解釋 他為什麼要解救艾希克。

The world is in turmoil:

世界陷入混亂：

robots have taken over, and only Ethic can set things right.

機器人主宰世界，只有 艾希克能恢復秩序。

In order to do so,

為了要重建秩序， 他們必須收集三件強大的物品，

they’ll need to collect three powerful artifacts

that are being used for nefarious purposes across the land.

這些物品在各地被用在 窮兇極惡的用途上。

Only then can Ethic return to the world machine— that giant crystal—

收集到手之後，艾希克 才能返回世界機器——巨型水晶，

to set things right.

去逆轉未來。

Ethic may have escaped the prison…

艾希克逃離了監獄……

but what has she gotten herself into?

她又將面臨怎樣的困境呢？