ENG  RUSTimus Online Judge
Online Judge
Problems
Authors
Online contests
About Online Judge
Frequently asked questions
Site news
Webboard
Links
Problem set
Submit solution
Judge status
Guide
Register
Update your info
Authors ranklist
Current contest
Scheduled contests
Past contests
Rules
back to board

Discussion of Problem 1619. Big Brother

How to prove the formula??? (-)


Edited by author 17.08.2008 22:54
How to prove the formula (+)
Posted by Eternal 5 Oct 2008 14:57
I found it in Shen's book (2004, Moscow) on 58 page (exercise 2.7.3). Actually answer is equal to (C^K_(M+K) - C^(K+1)_(M+K)) / C^K_(M+K) = 1 - M / (K+1). Also u should output 0 if M > K + 1

P.S. C^K_N = N!/(N-K)!/K!

Edited by author 05.10.2008 14:59
Re: How to prove the formula (+)
Posted by svr 21 Oct 2008 11:12
More reach sources: Ballot problem in Internet.
More useful information is all about random walking.
For example the problem 1148 Building towers very similar
but unsolved by many people.