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Monty Hall problem: Difference between revisions
add standard ml implementation
imported>Myrmidon (→{{header|Chapel}}: re-implemented using data parallelism which is simpler and about 10× faster) |
imported>Myrmidon (add standard ml implementation) |
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end monty;</syntaxhighlight>
=={{header|Standard ML}}==
Works with SML/NJ or with MLton using the SML/NJ Util library.
<syntaxhighlight lang="standard ml">
val pidint = Word64.toInt(Posix.Process.pidToWord(Posix.ProcEnv.getpid()));
val rand = Random.rand(LargeInt.toInt(Time.toSeconds(Time.now())), pidint);
fun stick_win 0 wins = wins
| stick_win trial wins =
let
val winner_door = (Random.randNat rand) mod 3;
val chosen_door = (Random.randNat rand) mod 3;
in
if winner_door = chosen_door then
stick_win (trial-1) (wins+1)
else
stick_win (trial-1) wins
end
val trials = 1000000;
val sticks = stick_win trials 0;
val stick_winrate = 100.0 * Real.fromInt(sticks) / Real.fromInt(trials);
(* if you lost by sticking you would have won by swapping *)
val swap_winrate = 100.0 - stick_winrate;
(print ("sticking = " ^ Real.toString(stick_winrate) ^ "% win rate\n");
print ("swapping = " ^ Real.toString(swap_winrate) ^ "% win rate\n"));
</syntaxhighlight>
'''Output'''
<pre>
sticking = 33.3449% win rate
swapping = 66.6551% win rate
</pre>
=={{header|Stata}}==
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