problem11.rb

#!/bin/env ruby

require 'benchmark'
class Array
    def map_with_index!
       each_with_index do |e, idx| self[idx] = yield(e, idx); end
    end

    def map_with_index(&block)
        dup.map_with_index!(&block)
    end
end

matrix = %Q{1 2 3 4 5 91
6 7 8 9 10 92
11 12 13 14 15 93
16 17 18 19 20 94
21 22 23 24 25 95
71 72 73 74 75 76}

matrix = %Q{1 2 3 4
6 7 8 9
11 12 13 14
16 17 18 19
21 22 23 24}

#
#01 02 03 04 05 91
#06 07 08 09 10 92 
#11 12 13 14 15 93
#16 17 18 19 20 94
#21 22 23 24 25 95
#71 72 73 74 75 76
#



#01 02 03 04 
#06 07 08 09
#11 12 13 14
#16 17 18 19
#
#-1234 -6789 -11-12-13-14 ???16-17-18-19
#-04081216 -01061116 -02071217 -03081318 ???04091419 -01071319 ???04081216
#[-[1, 7, 13, 19], -[1, 2, 3, 4], -[1, 6, 11, 16], -[2, 7, 12, 17], -[3, 8, 13, 18], -[6, 7, 8, 9], [4, 8, 14, 16], -[11, 12, 13, 14], -[4, 8, 12, 16]]
#
SIZE = 5

def mt(mat)
  mat.split(/[\r\n]/).map{|a| a.split(/\s/).map{|b| b.to_i} }
end
#m = mt(matrix)

xsize = 20
ysize = 20

def test(x,y, m, size)
  directions = [[-3..0, -3..0], [-2..1, -2..1],  [-1..2, -1..2], [0..3, 0..3],
                [[0,0,0,0], -3..0], [[0,0,0,0], -2..1],  [[0,0,0,0], -1..2], [[0,0,0,0], 0..3],
                [-3..0, [0,0,0,0]], [-2..1, [0,0,0,0]],  [-1..2,[0,0,0,0]], [0..3,[0,0,0,0]],
                [-3..0, [3,2,1,0]], [-2..1, [2,1,0,-1]],  [-1..2, [1,0,-1,-2]], [0..3, [0,-1,-2,-3]]]
  directions.map do |d|
    #puts d.inspect
    d[0].to_a.map_with_index {|dx, index|
        dy = d[1].to_a[index]
        #puts "x:#{x} dx:#{dx} y:#{y} dy:#{dy}"

        m[x+dx][y+dy]
    }.flatten if  (0..size).include?(x+d[0].first) &&
                  (0..size).include?(x+d[0].last) &&
                  (0..size).include?(y+d[1].first) &&
                  (0..size).include?(y+d[1].last)
  end.compact
end


#arrays = []
#(0..3).to_a.product((0..3).to_a).each {|a| arrays += test(a.first,a.last,m,3)}
#puts arrays.uniq.inspect
#__END__

r = Benchmark.measure do
GRID = %Q{08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48}

gr = mt(GRID).freeze

arrays = []
(0..19).to_a.product((0..19).to_a).each {|a| arrays += test(a.first,a.last,gr,19)}
products = arrays.map {|a| a.inject(1){|x,m| x*m} }
puts products.max
end
puts r.inspect