2. Same as 1, but if we want to find Nth from a permutation of M, K (M>=K and 1<= N <= P(M,K) ).

3. Same as 2. How about combination?

Spoiler for ...

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-) |

Guest Message by DevFuse

Started by Benson, Sep 27 2007 04:02 AM

2 replies to this topic

Posted 27 September 2007 - 04:02 AM

1. If we have 9 colors of buttons and want to find all its permutations, we know that is P(9,9)=9!=362880. So, we can't remember all of them or find it quick. That's fine. But, how we find Nth in these 362880 permutations without record it first?

2. Same as 1, but if we want to find Nth from a permutation of M, K (M>=K and 1<= N <= P(M,K) ).

3. Same as 2. How about combination?

2. Same as 1, but if we want to find Nth from a permutation of M, K (M>=K and 1<= N <= P(M,K) ).

3. Same as 2. How about combination?

Spoiler for ...

Posted 28 September 2007 - 06:38 AM

How do you determine an order? Without that, what does Nth mean?

- Bertrand Russell

Posted 28 September 2007 - 07:37 AM

How do you determine an order? Without that, what does Nth mean?

Hint

1. The question is asking to find a "method" to generate a Nth sequence. It is not asking what the Nth sequence is.

2. Since there's no original sequence, the order is not important or impact the result.

3. It is a permutation. So, Sequence(N) needs to be unique in 362880 permutations.

And, Inside the sequence, every one color button needs to be listed 1 times.

0 members, 0 guests, 0 anonymous users