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问道题# JobHunting - 待字闺中

P*b2010-08-18 07:08

1 楼

Given a deck of nCards unique cards, cut the deck iCut cards from top and pe
rform a perfect shuffle. A perfect shuffle begins by putting down the bottom
card from the top portion of the deck followed by the bottom card from the
bottom portion of the deck followed by the next card from the top portion, e
tc., alternating cards until one portion is used up. The remaining cards go
on top. The problem is to find the number of perfect shuffles required to re
turn the deck to its original order. Your

P*b2010-08-18 07:08

2 楼

没人感兴趣？

pe
bottom
the
e
go
re

【在 P*******b 的大作中提到】

: Given a deck of nCards unique cards, cut the deck iCut cards from top and pe
: rform a perfect shuffle. A perfect shuffle begins by putting down the bottom
: card from the top portion of the deck followed by the bottom card from the
: bottom portion of the deck followed by the next card from the top portion, e
: tc., alternating cards until one portion is used up. The remaining cards go
: on top. The problem is to find the number of perfect shuffles required to re
: turn the deck to its original order. Your

s*t2010-08-18 07:08

3 楼

请问后续的shuffle是可以自己定 iCut吗?还是说每次都是随机的?

pe
bottom
the
e
go
re

【在 P*******b 的大作中提到】

i*12010-08-18 07:08

4 楼

感兴趣的。想了下。没想到什么好办法。

P*b2010-08-18 07:08

5 楼

我感觉iCut不是每次都是随机

【在 s*****t 的大作中提到】

: 请问后续的shuffle是可以自己定 iCut吗?还是说每次都是随机的?
:
: pe
: bottom
: the
: e
: go
: re

s*t2010-08-18 07:08

6 楼

Okay, it seems to me that
just keep cutting the same iCuts and then shuffle the cards
finally, you will get the original deck.
Just I could not get the number of times of shuffle and could not prove it.
I suspect it is a ring problem, needs abstract algebra to solve it.

【在 P*******b 的大作中提到】

: 我感觉iCut不是每次都是随机