rabbit.rb

rabbit.rb

$holes = Array.new(100, false)
answer = rand($holes.count)
$holes[answer] = true

puts "Bunny is at index: #{answer}"

def move_bunny
  bunny_index = $holes.index(true)
  $holes[bunny_index] = false

  new_bunny_index = bunny_index

  if bunny_index == 0
    # bunny can only go to right
    new_bunny_index = bunny_index + 1
  elsif bunny_index == $holes.count - 1
    # bunny can only go to left
    new_bunny_index = bunny_index - 1
  elsif rand(2) == 0
    # go to left
    new_bunny_index = bunny_index - 1
  else
    # go to right
    new_bunny_index = bunny_index + 1
  end

  $holes[new_bunny_index] = true

  puts "Bunny moved to index: #{bunny_index} => #{new_bunny_index}"
end

i = 0
2.times do
  (0...($holes.count - 1)).step(1) do |_i|
    # by checking twice, the bunny will be always in even or odd hole
    # let's assume bunny is in even holes
    i = _i
    puts "Check index: #{i}"
    break if $holes[i]
    move_bunny

    puts "Check index: #{i}"
    break if $holes[i]
    move_bunny
  end

  if $holes.index(true) == i
    puts "Bunny is at index: #{i}"
    exit
  elsif
    # we didn't find the bunny, it must has been in odd holes
    # make a dummy check, this will force rabbit to be in even holes
    puts "DUMMY Check index: #{i}"
    move_bunny
  end
end

puts "Failed to find the bunny"