pathfinder

pathfinder.rb

#!/usr/bin/env ruby

class Input
  def initialize(name = 'input.txt', lines = rand(10..20))
    File.open(name, 'w+') do |file|
      lines.times do |i|
        file.puts (0..i).map { rand(-50..50) }.join(' ')
      end
    end
  end
end

class Pathfinder
  attr_reader :filename, :matrix

  def initialize(filename)
    @filename, @matrix = filename, {}

    File.open(filename, 'r').each.with_index do |line, index|
      @matrix[index] = line.split(/\s/).map(&:to_i)
    end
  end

  def path
    @path ||= begin
      offset = 0
      matrix.inject([]) do |path, (line, cortege)|
        maximum = nil
        maximum_index = 0
        cortege[ offset .. offset + 1 ].each.with_index do |element, column|
          if maximum != (maximum = maximum && [ maximum, element ].max || element)
            maximum_index = column + offset
          end
        end
        path << [ line, offset = maximum_index ]
      end
    end
  end

  def to_s
    @to_s ||= begin
      matrix.map do |line, cortege|
        point = path[line]
        cortege.map.with_index do |element, index|
          cell = element.to_s.rjust(3)
          point.last == index ? "\033[41m#{cell}\033[0m" : cell
        end.join(' ')
      end.join("\n")
    end
  end
end

Input.new
puts Pathfinder.new('input.txt')

Не компилируется:
dimko1.rb:7: warning: don't put space before argument parentheses
dimko1.rb:4:in rand': can't convert Range into Integer (TypeError) from dimko1.rb:4:ininitialize'
from dimko1.rb:51:in `new'
from dimko1.rb:51

это ruby 1.9 +

поставил с некоторыми заморочками ruby 1.9.3 на мак Lion, но все равно не компилируеся — ругается, что не может range конвертировать