#!/usr/bin/perl -w
$goat = 0;
$car = 1;
$n = 3000;
foreach $swap (0..1) {
  $win = 0;
  foreach (1..$n) {
    @curtains[0..2] = ($goat, $goat, $goat);
    $dice = int(rand(3));
    $curtains[$dice] = $car;
    $pick = int(rand(3));
    while (1) {
      $show = int(rand(3));
      if ($show == $pick) {next};
      if ($curtains[$show] == $car) {next};
      last;
    }
    if ($swap) {$pick = 3 - $show - $pick}
    if ($curtains[$pick] == $car) {$win++;}
  }
  print "$win of $n  =  " . int($win / $n * 100 + 0.5) . "% for ";
  if ($swap) {print "swapped\n"} else {print "not swapped\n"}
}