more library usage and readability improvements

db4
Jon Harper 2009-10-04 03:18:04 +09:00
parent 2dafa24383
commit a6a5245edb
1 changed files with 39 additions and 13 deletions
extra/project-euler/051

View File

@ -1,38 +1,60 @@
! Copyright (C) 2009 Jon Harper.
! See http://factorcode.org/license.txt for BSD license.
! http://projecteuler.net/index.php?section=problems&id=1
! DESCRIPTION
! -----------
! By replacing the first digit of *3, it turns out that
! six of the nine possible values:
! 13, 23, 43, 53, 73, and 83, are all prime.
! By replacing the third and fourth digits of 56**3 with the same digit,
! this 5-digit number is the first example having seven primes among
! the ten generated numbers, yielding the family:
! 56003, 56113, 56333, 56443, 56663, 56773, and 56993.
! Consequently 56003, being the first member of this family,
! is the smallest prime with this property.
!
! Find the smallest prime which, by replacing part of the number
! (not necessarily adjacent digits) with the same digit,
! is part of an eight prime value family.
! SOLUTION
! --------
! for each prime number, count the families it belongs to. When one reaches count of 8, stop, and get the smallest number by replacing * with ones.
USING: assocs kernel math math.combinatorics math.functions
math.parser math.primes namespaces project-euler.common
sequences sets strings grouping math.ranges arrays ;
sequences sets strings grouping math.ranges arrays fry math.order ;
IN: project-euler.051
<PRIVATE
SYMBOL: family-count
SYMBOL: large-families
: reset-globals ( -- )
H{ } clone family-count set
H{ } clone large-families set ;
: append-or-create ( value seq/f -- seq )
dup [ swap suffix ] [ drop 1array ] if ;
: append-at ( value key assoc -- )
[ at append-or-create ] 2keep set-at ;
: digits-positions ( str -- positions )
H{ } clone swap over [ swapd append-at ] curry each-index ;
: digits-positions ( str -- positions )
H{ } clone [ '[ swap _ push-at ] each-index ] keep ;
: *-if-index ( char combination index -- char )
member? [ drop CHAR: * ] when ;
: replace-positions-with-* ( str positions -- str )
[ *-if-index ] curry map-index ;
: all-size-combinations ( seq -- combinations )
: all-positions-combinations ( seq -- combinations )
dup length [1,b] [ all-combinations ] with map concat ;
: families ( stra -- seq )
dup digits-positions values
[ all-size-combinations [ replace-positions-with-* ] with map ] with map concat ;
[ all-positions-combinations [ replace-positions-with-* ] with map ] with map concat ;
: save-family ( family -- )
family-count get dupd at 8 = [ large-families get conjoin ] [ drop ] if ;
dup family-count get at 8 = [ large-families get conjoin ] [ drop ] if ;
: increment-family ( family -- )
family-count get dupd at* [ 1 + ] [ drop 1 ] if swap family-count get set-at ;
family-count get inc-at ;
: handle-family ( family -- )
[ increment-family ] [ save-family ] bi ;
@ -52,7 +74,11 @@ SYMBOL: large-families
: (euler051) ( i -- answer )
dup test-n-digits-primes
dup assoc-size 0 >
[ nip values [ fill-*-with-ones string>number ] map infimum ]
[ nip values [ fill-*-with-ones string>number ] [ min ] map-reduce ]
[ drop 1 + (euler051) ] if ;
PRIVATE>
: euler051 ( -- answer )
2 (euler051) ;
SOLUTION: euler051