Calculting monty hall effect for starcraft zergling scouting (Sam)

calculate-scouting-success.rb

class Array
  def select_random
    return self.sample
  end

  def select_random_that_isnt(*excluded_vals)
    selected_value = self.select_random
    
    if excluded_vals.include? selected_value
      return self.select_random_that_isnt(*excluded_vals)
    else return selected_value end
  end
end

num_simulation_attempts = 1000000
num_spawn_locations = 3
overlord_always_finds_an_empty_slot = true


spawn_locations = (1..num_spawn_locations).to_a

wins = 0

num_simulation_attempts.times do
  enemy_base_location = spawn_locations.select_random  
  zergling_choice = spawn_locations.select_random

  overlord_choice =
    if overlord_always_finds_an_empty_slot
      spawn_locations.select_random_that_isnt(zergling_choice, enemy_base_location)
    else
      spawn_locations.select_random_that_isnt(zergling_choice)
    end

  swapped_zergling_choice =
    spawn_locations.select_random_that_isnt(zergling_choice, overlord_choice)

  if swapped_zergling_choice == enemy_base_location
    wins = wins + 1
  end
end

puts wins.to_f / num_simulation_attempts