Paste: Problem 18 - Project Euler

Author: Woo-Kyoung Noh
Mode: factor
Date: Tue, 13 Oct 2009 14:35:39
Plain Text | 
! http://projecteuler.net/index.php?section=problems&id=18
! problem18.factor
!                           wookay.noh at gmail.com
 
USING: splitting math math.parser sequences kernel arrays ascii prettyprint ;
IN: problem18
 
: duex_at ( seq pos -- x y )
  dup 2 + rot subseq first2 ;
 
: bigger ( pos x y -- val pos )
  2dup > [ drop ] [ nip [ 1 + ] dip ] if swap ;
 
: trian ( seq pos seq -- seq pos )
  dup length 1 = [ first swap ] [ 2dup drop duex_at bigger ] if -rot suffix swap ;
 
: route ( seq -- result )
  { } 0 rot [ first " " split [ string>number ] map trian ] each drop sum ;
 
: split-lines ( seq -- data )
  [ blank? ] trim "\n" split [ { } swap suffix ] map ;
 
 
 
"""
3
7 4
2 4 6
8 5 9 3
""" split-lines route .
 
 
"""
75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
""" split-lines route .
 
 
USE: simple-flat-file
"triangle.txt" data route .

Annotation: ruby version

Author: Woo-Kyoung Noh
Mode: ruby
Date: Tue, 13 Oct 2009 14:36:19
Plain Text | 
def route s
  c = 0
  s.strip.lines.map do |line|
    a,b = line.split(' ').map(&:to_i)[c..c.next]
    r,c = a.to_i>b.to_i ? [a,c] : [b,c.next]
    r
  end.inject(0){|s,n| s+n }
end

puts route("""
3
7 4
2 4 6
8 5 9 3
""")

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