problem 88

88.rb

min = 2
max = 100

min.upto(max) do |count|
  puts "k=#{count}"

  a = (1..count).to_a
  options = a.repeated_combination(count).to_a

  for option in options.reverse
    addition_total = 0
    multiplication_total = 1
    for number in option do
      addition_total += number
      multiplication_total *= number
    end
    if addition_total == multiplication_total
      puts "#{addition_total} = #{option}"
      break
    end
  end

end

output.sh

➜  Desktop  ruby 88.rb
k=2
4 = [2, 2]
k=3
6 = [1, 2, 3]
k=4
8 = [1, 1, 2, 4]
k=5
8 = [1, 1, 2, 2, 2]
k=6
12 = [1, 1, 1, 1, 2, 6]
k=7
12 = [1, 1, 1, 1, 1, 3, 4]
k=8
12 = [1, 1, 1, 1, 1, 2, 2, 3]
k=9
15 = [1, 1, 1, 1, 1, 1, 1, 3, 5]
k=10
16 = [1, 1, 1, 1, 1, 1, 1, 1, 4, 4]
k=11
16 = [1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 4]
k=12
16 = [1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2]
k=13
18 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 3]
k=14
20 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 5]
k=15
24 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 8]
k=16
24 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 6]
k=17
24 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 6]
k=18
24 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4]
k=19
24 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 3]
k=20
28 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 7]