All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Gossip (Posted on 2012-07-26) Difficulty: 3 of 5
n people know each a different piece of gossip.

They can phone each other and exchange all they know so that after the call the parties know anything that either of them knew before the call.

What is the smallest number of calls needed so that everyone knows everything and how is this number achieved?

No Solution Yet Submitted by Ady TZIDON    
Rating: 4.5000 (2 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: Solution | Comment 10 of 12 |
(In reply to Solution by Hugo)

I missed the example you gave for 5 persons (actually no example was given, only the formula for n > 4. Sloane OEIS A058992 does indeed give the formula a(n) = 2n - 4 for n >=4.
To be more complete, as the sequence in Sloane provides the first three terms of the sequence as 0, 1, 3:
a(n) = 0 for n = 1
a(n) = 1 for n = 2
a(n) = 3 for n = 3
a(n) = 2n - 4 for n >=4.

  Posted by Dej Mar on 2012-07-27 17:48:28
Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (5)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2018 by Animus Pactum Consulting. All rights reserved. Privacy Information