作者xmisery (misery)
看板Grad-ProbAsk
标题Re: [问题] 离散问题请教?
时间Wed Mar 18 17:41:07 2009
※ 引述《christensen ()》之铭言:
: 1. Given a big-O estimate for f(n)=nlog(n!)+n^2+(sin n)^4
: use a simple function of smallest order, f(n) = _____________
nlog(n!)=O(n^2lgn)
∴fn(n)=O(n^2lgn)
: 2. The solution for the recurrence relaion a = a + (n-1), n >=2, a1=5
: n n-1
: is _____________.
a =a +(n-1)=a +(n-2)+(n-1)=a +1+…+(n-1)=a +n(n-1)/2=n(n-1)/2 + 5
n n-1 n-2 n-(n-1) 1
: 3. consider the game rule: "Given 17 stones in a pile, two players take
: turns removing 1, 2, or 3 stones, and whoever takes the last stone loses."
: Design a strategy to guarantee one player a win and show your answer
: step by step.
: 请顺便告知求解过程拜托了 原po太笨 X(
剩先後 剩先後 剩先後 剩先後 剩先
17 1 3 13 1 3 9 1 3 5 1 3 1 1
3 1 3 1 3 1 3 1 输
2 2 2 2 2 2 2 2
如上取法可确保後取者赢
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