#!/usr/bin/perl -w

use strict;
use warnings;

srand();

my $maxday = 365;
my $TRIALS = 1024000;
my $average = 0;
my $sum = 0;
my $tenpercent = $TRIALS / 10;

for (my $count = 0; $count < $TRIALS; $count++) {
	$sum += &test_bdays($maxday);
	if (($count) and (!($count % $tenpercent)))	{
		$average = ($sum * 1.0) / $count;
		print("After $count trials, ", 
"the average number of people in the room was $average\n");
	}
}
$average = ($sum * 1.0) / $TRIALS;
print("After $TRIALS trials, ", "
the average number of people in the room was $average\n");

sub test_bdays {
	my ($mday) = @_;
	my @days = ();
	my $d = $mday;
	my $people = 0;
	while ($d) {
		$days[$d] = 0;
		$d--;
	}
	my $flag = 0;
	while (!($flag)) {
		$people++;
		my $index = int(rand() * $mday);
		$days[$index]++;
		$flag = ($days[$index] > 1);
	}
	return($people);
}