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The family of giants you work for is throwing a fancy dinner party, and they all want to look their best.
你工作的巨人家庭打算开一个别开生面的晚会派对，所以他们都希望凸显自己最好的一面。
But there's a problem -- the elder giant's favorite shirt is wrinkled!
但是，有个问题--比较年长的巨人最喜欢的衣服皱了！
To fix it, you'll need to power up... the Giant Iron.
为了解决它，你需要启动...巨大的熨斗。
The iron needs two giant batteries to work.
这个巨大的熨斗需要两个巨大的电池运作。
You just had 4 working ones and 4 dead ones in separate piles, but it looks like the baby giant mixed them all up.
你只有四个正常运作的电池，还有四个耗损了的电池在不同的电池堆里，但是看来巨人宝宝把它们给混在一起了。
You need to get the iron working and press the giant shirt, fast -- or you'll end up being the main course tonight!
你需要让熨斗运作，然后烫巨人的衣服，而且要很快--不然的话，你就是今晚的主菜！
How can you test the batteries so that you're guaranteed to get a working pair in 7 tries or less?
你能够如何测试电池，以确保你能够在七个或以下的尝试内就找到一对可用的电池？
You could, of course, take all eight batteries and begin testing the 28 possible combinations.
你当然可以拿全部八个电池，然后开始试试二十八个可能的组合。
You might get lucky within the first few tries.
你可能在初开始的几个尝试就很幸运。
But if you don't, moving the giant batteries that many times will take way too long.
但是若不然，移动大电池这么多次会消耗太多时间。
You can't rely on luck -- you need to assume the worst possibility and plan accordingly.
你不能靠运气--你需要作最坏的打算，然后做好策划。
However, you don't actually need to test every possible combination.
但是，你其实不需要尝试所有的可能组合。
Remember -- there are four good batteries in total, meaning that any pile of six you choose will have at least two good batteries in it.
记得--总共有四个好的电池，也就是说在任何六个电池的组合里，会有至少两个好的电池。
That doesn't help you right away, since testing all six batteries could still take as many as 15 tries.
那没有直接帮助到你，因为尝试所有六粒电池还是需要十五次的尝试。
But it does give you a clue to the solution -- dividing the batteries into smaller subsets narrows down the possible results.
但是，它给了你解决方案的提示--把电池分成小组缩小可能的结果。
So instead of six batteries, let's take any three.
所以，与其六个电池，让我们拿任何三个。
This group has a total of three possible combinations.
这个小组有三个组合。
Since both batteries have to be working for the iron to power up,
因为要让熨斗运作需要两个电池都正常运作，
a single failure can't tell you whether both batteries are dead, or just one.
其中一个失败并不会告诉你是两个电池都不能用，还是只是其中一个。
But if all three combinations fail, then you'll know this group has either one good battery, or none at all.
但是若三个组合都失败，你就能够知道这个小组里是有一个好的电池，或一个也没有。
Now you can set those three aside and repeat the process for another three batteries.
现在你可以把这三个放在一边了，然后在另外三个电池重复同样的过程。
You might get a match, but if every combination fails again, you'll know this set can have no more than one good battery.
你有可能得到对的组合，但是若每个组合都又失败，那你就知道这个组合不可能有超过一个好的电池。
That would leave only two batteries untried.
那最后你剩下两个还未试过的电池。
Since there are four good batteries in total and you've only accounted for two so far, both of these remaining ones must be good.
因为总共有四个好的电池而你只处理了两个，这剩下的两个必然是好的。
Dividing the batteries into sets of 3, 3, and 2 is guaranteed to get a working result in 7 tries or less,
把电池分成三、三、二，必然能够在七次尝试找到可行的结果，
no matter what order you test the piles in.
无论你是用什么次序尝试。
With no time to spare, the iron comes to life, and you manage to get the shirt flawlessly ironed.
在没有剩余时间的情况下，熨斗开始运作了，而你也成功地把衣服没有瑕疵地烫好了。
The pleased elder and his family show up to the party dressed to the nines... well, almost.
那个欢喜的年长巨人和他的家人衣着隆重地参加了派对...嗯，差不多如此。
