my @vals = sort {$b <=> $a } map { values %{$hoh->{$_}} } keys %$hoh;
my ($one, $two, $three) = @vals[0..2];
[download]

Update Completely missed that tinita had an almost identical solution below. In the case of a very large HoH, you can avoid sorting and gain a bit of efficiency with the following:

my @top_3;
my $filled = 0;
VAL:
for my $val ( map { values %{$hoh->{$_}} } keys %$hoh ) {
    if ( ! $filled ) {
        for ( 0 .. 2 ) {
            if ( ! defined $top_3[$_] ) {
                $top_3[$_] = $val;
                $filled = 1 if $_ == 2;
                next VAL;
            }
        }
    }
    if ( $val > $top_3[0] ) {
        ($top_3[0], $top_3[1]) = ($val, $top_3[0]);
    }
    elsif ( $val > $top_3[1] ) {
        ($top_3[1], $top_3[2]) = ($val, $top_3[1]);        
    }
    elsif ( $val > $top_3[2] ) {
        $top_3[2] = $val;
    }
}
print "$_\n" for @top_3;
[download]

Well (d'oh), an important thing I forgot to mention is that I also need to know where I am in the $HoH for any given value. So I not only need to find the top x (10 in my case) values of $HoH->{$foo}{$bar}, but I also need to keep track of the value of $foo and $bar for each of those x values.

Anyway, your code gave me some idea and this is what I've come up with for now.

while (my $kid_ = $kills_sth->fetchrow_hashref()){
    $KP->{$kid_->{k}}{$kid_->{v}}++;
}
# How many do we keep?
my $total = 10;
my %top;

for(keys %{$KP}){
    # Player ID
    my $pid = $_;
    VAL:
    for ( keys %{$KP->{$pid}}) {
        # Target ID
        my $tid = $_;
        my $frags  = $KP->{$pid}{$tid};
        for(0 .. ($total - 1)){
            my $idx = $_;
            $top{$idx}{f} ||= 0;
            if(($idx != ($total - 1)) && $frags > $top{$idx}{f}){
                my $idx2 = $idx + 1;
                $top{$idx2}{k}   = $top{$idx}{k};
                $top{$idx2}{v}   = $top{$idx}{v};
                $top{$idx2}{f}   = $top{$idx}{f};
                $top{$idx}{k}    = $pid;
                $top{$idx}{v}    = $tid; 
                $top{$idx}{f}    = $frags; 
                next VAL;
            }
            elsif(($idx == ($total - 1)) && ($frags > $top{$idx}{f})){
                $top{$idx}{k} = $pid;
                $top{$idx}{v} = $tid;
                $top{$idx}{f} = $frags;
                next VAL;
            }
        }
    }
}

for(0 .. ($total - 1)){
    my $id = $_;
    printf("%2s. p: %s\tt: %s\tf: %s\n",($id+1),$top{$id}{k},$top{$id}
+{v},$top{$id}{f});
}
[download]

Still, it seems awfully inefficient to me and I'm really leary of it's ninja scaling abilities. But that said, it works and produces the intended results:

 1. p: 2838413  t: 3440380      f: 328
 2. p: 2838413  t: 1261188      f: 282
 3. p: 539960   t: 2976790      f: 273
 4. p: 3440380  t: 2838413      f: 268
 5. p: 182560   t: 53957        f: 206
 6. p: 539960   t: 53957        f: 196
 7. p: 1261188  t: 53957        f: 190
 8. p: 539960   t: 3440380      f: 171
 9. p: 3440380  t: 539960       f: 146
10. p: 53957    t: 1261188      f: 127
[download]


I'd appreciate any ideas about increasing efficiency.

Thanks a bunch for your help.

ps. Yes, it's a half-life stats program. :)

doran,
I think you might find the following a bit more efficient and a bit more readable:

# An inline loop is more efficient then a block - thought almost imper
+ceptable
$KP->{ $_->{k} }{ $_->{v} }++ while $kills_sth->fetchrow_hashref();

# Before I did not know if it was safe to assume no negative numbers -
+ now I can
my %top = map { $_ => {'score' => 0, 'pid' => '', 'tid' => ''} } 1 .. 
+10; 

my @items = qw(score pid tid);

for my $pid ( keys %{ $KP } ) {
    SCORE:
    for my $tid ( keys %{ $KP->{$pid} } ) {
        my $score  = $KP->{$pid}{$tid};
        next if $score < $top{10}{score};    # May or may not improve 
+efficiency
        for my $rank ( 1 .. 10 ) {
            if ( $score > $top{$rank}{score} ) {
                (@{$top{$rank}}{@items}, @{$top{$rank + 1}}{@items}) =
+ ($score, $pid, $tid, @{$top{$rank}}{@items});
                next SCORE;
            }
        }
    }
}

for my $rank ( 1 .. 10 ) {
    printf("%.2d. f: %s\tp: %s\tt: %s\n", $rank, @top{@items});
}
[download]

This would be much more efficient if it could be done with SQL. You would have to provide more info to determine that.

Cheers - L~R

Update: 2004-03-17 This is broken. To fix it you would make %top an AoA, handle fence post issues, and splice entries in the middle while popping off the end. This version will randomly lose values. See this for a working example.