#!/bin/env ruby
require 'pry'
numbers = File.read('./input').split("\n").map(&:to_i).sort
numbers.prepend(0)
numbers.push(numbers[-1] + 3)
#binding.pry
solution = numbers.map.with_index do |num, i|
    next if i == 0
    num - numbers[i-1]
end
solution.compact!
count = [0]
count_i = 0
solution.each.with_index do |num, i|
    next if i == 0
    if num == 3
        count_i += 1
        count.push(0)
        next
    end
    count[count_i] += 1 if solution[i-1] == 1
end

count.delete(0)
count.map! do |num|
    case num
    when 1
        2
    when 2
        4
    when 3
        7        
    end
end

p count.reduce(:*)