a**a
发帖数: 416 | 1 nod.
给12个球如此编号：
1: 00L
2: 0LR
3: 0R0
4: 0LL
5: LRR
6: RL0
7: LRL
8: R0R
9: L00
10: R0L
11: LLR
12: RR0
编号的每一位(对应一次称重)代表该球在该次称重中是
0:不上天平
L:上天平左
R:上天平右
再定义称重结果为左重为L,右重为R,平衡为0.
根据称重结果，如果可以找到对应编号的球，则说明此球为重。否则把结果逐位求反(L
->R,R->L)，必能找到相应编号的球，这说明该球为轻。
当球数增加到13时，只能增加一个编号000,如果碰巧该球为目标球，则无法知其轻重。 | t****n
发帖数: 1347 | 2 好象打有 rec.puzzles 那年就有这题,
rec.puzzles 的老版本 faq 里还有很多有趣的题目.
此题原文与答案, the labeling is interesting:
2.1. ==> balance <== [logic/part5]
You have 12 coins, one of which is counterfeit. The counterfeit is
indistinguishable from the rest except that it is either heavier or
lighter (but you don't know which). How can you determine which coin is
the counterfeit in 3 weighings on a balance scale?
One solution is to label the coins with the letters from FAKE MIND CLOT
and weigh the coins: MA DO -- LIK | t****n
发帖数: 1347 | 3 BTW, rec.puzzles stuff can be found at:
http://einstein.et.tudelft.nl/~arlet/puzzles/index.html
【在 t****n 的大作中提到】
: 好象打有 rec.puzzles 那年就有这题,
: rec.puzzles 的老版本 faq 里还有很多有趣的题目.
: 此题原文与答案, the labeling is interesting:
: 2.1. ==> balance <== [logic/part5]
: You have 12 coins, one of which is counterfeit. The counterfeit is
: indistinguishable from the rest except that it is either heavier or
: lighter (but you don't know which). How can you determine which coin is
: the counterfeit in 3 weighings on a balance scale?
: One solution is to label the coins with the letters from FAKE MIND CLOT
: and weigh the coins: MA DO -- LIK
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