jugs.rb

=begin
Given 2 water jugs of different sizes and an unlimited source of water, perform different operations to end up with some goal amount of water.

Write out the operations and how much water is in the jugs at each step.

Problem 1 --- Small = 3, Big = 5, Goal = 4
- Start (0, 0)
- Fill small (3, 0)
- pour to big (0, 3)
- Fill small (3, 3)
- Pour from small to big (1, 5)
- Empty big (1, 0)
- Pour from small to big (0, 1)
- fill small (3, 1)
- pour small to big (0, 4)


Problem 2 --- Small = 5, Big = 7, Goal = 1
- Start (0, 0)
- fill small (5, 0)
- pour small into big (0, 5)
- fill small (5, 5)
- pour small into big (3, 7)
- Empty big (3, 0)
- pour small into big (0, 3)
- fill small (5, 3)
- pour small into big (1, 7)


Problem 3 --- Small = 7, Big = 11, Goal = 3
- Start (0, 0)
- fill small (7, 0)
- pour small into big (0, 7)
- fill small (7, 7)
- pour small into big (3, 11)
=end
  
def fill_jugs(small_jug_max, big_jug_max, goal)
  # Print steps to console
  small_jug = 0
  big_jug = 0
  
  puts '- Start (0, 0)'
  
  while small_jug != goal && big_jug != goal
    if small_jug == 0
      small_jug = small_jug_max
      puts "- Fill small (#{small_jug}, #{big_jug})"
    elsif big_jug < big_jug_max
      # pour small into big (0, 7)
      total = small_jug + big_jug
      big_jug = total > big_jug_max ? big_jug_max : total
      small_jug = total - big_jug
      puts "- Pour small into big (#{small_jug}, #{big_jug})"
    else
      # fill small (7, 7)
      big_jug = 0
      puts "- Empty big (#{small_jug}, #{big_jug})"
    end
  end
  
  puts "Finished!\n\n"
end

fill_jugs(3, 5, 4)
fill_jugs(5, 7, 1)
fill_jugs(7, 11, 3)