24 lines
789 B
Elixir
24 lines
789 B
Elixir
defmodule MontyHall do
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def simulate(n) do
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{stay, switch} = simulate(n, 0, 0)
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:io.format "Staying wins ~w times (~.3f%)~n", [stay, 100 * stay / n]
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:io.format "Switching wins ~w times (~.3f%)~n", [switch, 100 * switch / n]
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end
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defp simulate(0, stay, switch), do: {stay, switch}
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defp simulate(n, stay, switch) do
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doors = Enum.shuffle([:goat, :goat, :car])
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guess = :rand.uniform(3) - 1
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[choice] = [0,1,2] -- [guess, shown(doors, guess)]
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if Enum.at(doors, choice) == :car, do: simulate(n-1, stay, switch+1),
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else: simulate(n-1, stay+1, switch)
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end
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defp shown(doors, guess) do
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[i, j] = Enum.shuffle([0,1,2] -- [guess])
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if Enum.at(doors, i) == :goat, do: i, else: j
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end
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end
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MontyHall.simulate(10000)
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