1 ! Copyright (c) 2008 Eric Mertens
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: kernel math sequences locals ;
8 ! sequence helper functions
10 : partial-sums ( seq -- seq )
11 0 [ + ] accumulate swap suffix ; inline
13 : generate ( n quot -- seq )
14 [ drop ] swap compose map ; inline
16 : map-infimum ( seq quot -- min )
17 [ min ] compose 0 swap reduce ; inline
20 ! triangle generator functions
22 : next ( t -- new-t s )
23 615949 * 797807 + 1 20 shift mod dup 1 19 shift - ; inline
25 : sums-triangle ( -- seq )
26 0 1000 [ 1+ [ next ] generate partial-sums ] map nip ;
30 :: (euler150) ( m -- n )
31 [let | table [ sums-triangle ] |
38 ] map partial-sums infimum