Just keep the best three results so far: 
use List::Util qw{ first };

sub subDiscarder {
    my @top3 = map [0, 0, -inf], 0 .. 2;
    for my $minion (@{ $_[0] }) {
        next if $minion->[2] < $top3[2][2];
        my $idx = first { $top3[$_][2] <= $minion->[2] } 0 .. 2;
        splice @top3, $idx, 0, $minion;
        splice @top3, 3;
    }
    @{ $_[0] } = @top3;
}

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لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: sorting array of arrays reference by choroba
in thread sorting array of arrays reference by kimlid2810

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