推 gensim:你是對的!! 12/20 01:19
→ killerjoe:謝謝~ 12/22 00:23
Eleven scientists are working on a secret project. They wish to lock up
the documents in a cabinet such that the cabinet can be open if and only if
six or more of scientists are present.What is the smallest number of keys to
the locks each scientist must carry?
解答寫要C(10,3)個keys
為什麼不是C(10,5)?
我的想法是
A必須持有任5位scientists所沒有的key才能打開
而從10位scientist取5位有C(10,5)種取法
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