#!/usr/local/bin/perl 

$teams=$ARGV[0];
if (@ARGV<1){
    print "Input an number of teams: ";
    $teams = <STDIN>;
    chomp $teams;
}
if ($teams<=0 || !defined $teams || $teams+0 ne $teams){
   die("I said a number...\a\n");
}
$teams = int $teams;
if ($teams%2==1){
    $partidos=int $teams/2;    # 
    $jornadas= $teams-1;     # a una vuelta 
}else{
    $partidos = $teams/2;
    $jornadas= $teams-1;
}
BOOT:
$c=0;
@f=();
%h=();
print "\n";
for $x (1..$jornadas){
    print "\n$x)\t";
    for $y (1..$partidos){
LOOP:
	  $c++;
	if ($c>100000){ goto BOOT; }
	$i = 1 + int rand $teams;
	$j = 1 + int rand $teams;
	if ($i==$j) { goto LOOP; }
	for $z (1..$y-1){
	    if ($f[$x][$z]=~ /^$i\:/i ||
	    $f[$x][$z]=~ /\:$i\z/i){ goto LOOP; }
	    if ($f[$x][$z]=~ /^$j\:/i ||
	    $f[$x][$z]=~ /\:$j\z/i){ goto LOOP; }
	}
	if ($h{$i.$j}==1) { 
	    if ($h{$j.$i}!=1){ ($i,$j)=($j,$i); }
	    else { goto LOOP; }
	}
	$h{$i.$j}++;
	$f[$x][$y]="$i:$j";
	print "$f[$x][$y] "; 
    }  
}
print "\n\n";

__END__