#!/usr/bin/perl -w
use strict;
$|++;


my $number = $ARGV[0] || die("Usage: trivec.pl number$/");
my $vecTri;

$vecTri = createTriVec( $number );
print $/, findTriCombo( $vecTri, $number );

sub createTriVec
{
    my $upper = $_[0] || 99;
    my $vec = "\0";
    my $guess = 0;
    for( my $num = 1; $guess+$num <= $upper; $num++ )
    {
        $guess+=$num;
        vec( $vec, $guess, 1 ) = 1;
    }
    return $vec;
}

sub findTriCombo
{
    my $vec = $_[0] || return undef;
    my $num = $_[1] || return undef;
    my @tris;
    my $sum = 0;
    push(@tris, $num, 0, 0), return "@tris" if( vec( $vec, $num, 1 ) );
    my $i = $num-1;
    while( $i > 0 )
    {
# print "<i $i>\t<s $sum>\t<t @tris>$/"; # UNCOMMENT TO SEE WHAT'S GOING ON...
        if( scalar @tris >= 3 ) {
            $i = $tris[0] - 1;
            @tris = ();
            $sum = 0;
        }
        if( vec( $vec, $i, 1 ) )
        {
            push @tris, $i;
            $sum += $i;
            $i = $num - $sum;
            next;
        }
        else
        {
            $i--;
        }
    }
    if( $sum == $num )
    {
        push(@tris, 0) while @tris < 3;
        return "@tris";
    }
    return "not found!";
}