Add meta data to Project Euler problem 186

db4
Aaron Schaefer 2008-11-03 19:02:57 -05:00
parent 9152b6d5f0
commit 9be67e7df7
1 changed files with 41 additions and 2 deletions

View File

@ -1,7 +1,43 @@
USING: circular disjoint-sets kernel math math.ranges
sequences ;
! Copyright (c) 2008 Eric Mertens.
! See http://factorcode.org/license.txt for BSD license.
USING: circular disjoint-sets kernel math math.ranges sequences ;
IN: project-euler.186
! http://projecteuler.net/index.php?section=problems&id=186
! DESCRIPTION
! -----------
! Here are the records from a busy telephone system with one million users:
! RecNr Caller Called
! 1 200007 100053
! 2 600183 500439
! 3 600863 701497
! ... ... ...
! The telephone number of the caller and the called number in record n are
! Caller(n) = S2n-1 and Called(n) = S2n where S1,2,3,... come from the "Lagged
! Fibonacci Generator":
! For 1 <= k <= 55, Sk = [100003 - 200003k + 300007k^3] (modulo 1000000)
! For 56 <= k, Sk = [Sk-24 + Sk-55] (modulo 1000000)
! If Caller(n) = Called(n) then the user is assumed to have misdialled and the
! call fails; otherwise the call is successful.
! From the start of the records, we say that any pair of users X and Y are
! friends if X calls Y or vice-versa. Similarly, X is a friend of a friend of Z
! if X is a friend of Y and Y is a friend of Z; and so on for longer chains.
! The Prime Minister's phone number is 524287. After how many successful calls,
! not counting misdials, will 99% of the users (including the PM) be a friend,
! or a friend of a friend etc., of the Prime Minister?
! SOLUTION
! --------
: (generator) ( k -- n )
dup sq 300007 * 200003 - * 100003 + 1000000 rem ;
@ -35,4 +71,7 @@ IN: project-euler.186
: euler186 ( -- n )
<generator> 0 1000000 <relation> (p186) ;
! [ euler186 ] 10 ave-time
! 18572 ms ave run time - 796.87 SD (10 trials)
MAIN: euler186