max sum path

max_sum_path.rb

#!/usr/bin/env ruby

def max_path_sum(file)

  input = File.open(file).readlines

  numbers = input.collect { |line| line.split(" ").map(&:to_i) }

  # started from the bottom
  triangle_size = numbers.size - 2

  triangle_size.downto(0).each do |row|

    (0 .. numbers[row].size - 1).each do |col|

      if numbers[row + 1][col] > numbers[row + 1][col + 1]
        max = numbers[row + 1][col]
      else
        max = numbers[row + 1][col + 1]
      end

      numbers[row][col] += max

      puts row
      puts numbers[row][col]
    end

  end

  # now we here
  numbers[0][0]

end

puts max_path_sum('triangle.txt')