Similar to Random_Walk version (Re: Limit the size of a hash), but without sort.

Here, we keep five elements.

If necessary, we calculate the index of the lowest element (min of highest).

If score of the new element is better than "min of highest", "min of highest" is replaced by new element.

use strict;
use warnings;
my $keep = 5;
#init
my @highest = map scalar<DATA>,1..$keep; #fisrt lines
my @scores = map +(split)[-1],@highest; #score is last element (-1) of
+ each line
my $indexofmin = 0;
my $updated = 1;
####

while(my $line=<DATA>) {
    my $score = (split/ /,$line)[-1];
    if ($updated) {
        for my $i (0..$#scores) {
            $indexofmin = $i if $scores[$i]<$scores[$indexofmin];
        }
    }
    if ($score>$scores[$indexofmin]) {
        $highest[$indexofmin]=$line;
        $scores[$indexofmin]=$score;
        $updated = 1;
    } else {
        $updated = 0;
    }
}
print @highest;

__DATA__
0 5 3 7   0.97
1 5 4 8   0.18
1 5 4 8   0.21
1 5 4 8   0.22
1 5 4 8   0.52
1 5 4 8   0.16
1 5 4 8   0.18
1 5 4 8   0.72
1 5 4 8   0.32
1 5 4 8   0.17
1 5 4 8   0.52
1 5 4 8   0.92
6 8 4 6   0.54
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