Re: [理工] [離散] 98台大電機
假設1為改變status，0為不改變
locker 1 2 3 4 5 6 7 ‧‧‧
student1 1 1 1 1 1 1 1 ‧‧‧
student2 0 1 0 1 0 1 0 ‧‧‧
student3 0 0 1 0 0 1 0 ‧‧‧
student4 0 0 0 1 0 0 0 ‧‧‧
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locker還是open的條件是該行為1的bit數有奇數個，
每個locker在遇到編號的因數時該列bit會是1
所以最後是open的locker它的編號的因數為奇數個
即完全平方數，所以是1,4,9,16,25,36,49,64,81,100
※ 引述《ceo890710 (Drinking)》之銘言：
: ---------------------------------------------------------------------
: One hundred students enter a locker room that contains 100 lockers.
: The first student open all the lockers.The second student changes the
: status(from open to closed, and vice versa) of every other locker,
: starting with the second locker.The third student then changes the
: status of every third locker,starting with the third locker.In general,
: for 1<=K<=100,the kth student changes the status of every kth locker,
: starting with the kth locker.After the 100th student has gone through
: the lockers,which lockers are left open?
: 想問一下這題大家會怎麼解?
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※ 發信站: 批踢踢實業坊(ptt.cc)
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08/01 18:36, , 1F
08/01 18:36, 1F
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08/02 00:06, , 2F
08/02 00:06, 2F
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08/02 08:16, , 3F
08/02 08:16, 3F
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08/03 20:27, , 4F
08/03 20:27, 4F
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