decomposition.rb

class Rabbit

  @@result = 0

  def initialize(path = "./input")
    File.open(path, "r") do |file|  
      file.each_line do |line|
        line = line.split
        short_path(line[0].to_i, line[1].to_i)
      end
    end
  end  

private 

  def short_path(jump, total)
    optimal_jumps = []
    while total >= jump do
      total -= jump
      optimal_jumps << jump
    end
    optimal_jumps << total if total > 0
    decomposition(optimal_jumps)
    puts @@result ##
  end

  def decomposition(jumps)
    combinations(jumps)
    jumps.each do |jump| 
      numbers = []
      if jump > 1
        numbers << jump 
        numbers.each do |number| 
          while number > 1 do
            numbers[0] -= 1 
            numbers << 1
            # call combinations. 
            # if i make decomposition for 5 there will never be 2 + 2 + 1 in this case
          end 
        end      
      end

    end
  end

  def dec(nums)

  end 

  def combinations(jumps)
    same = {}
    factorial_arr = []  
    jumps.each { |jump| same[jump] == nil ? same[jump] = 1 : same[jump] += 1 }
    n = (1..jumps.count).inject(1, :*)
    same.values.each { |value| factorial_arr << (1..value).inject(1, :*) }
    r = factorial_arr.inject(:*)
    @@result += (n / r)     
  end   

end

Rabbit.new