If I've got a grasp on your problem, what you want to do is sort a list of IDs by their associated point values. You certainly could do that with a hash, where the IDs are keys and the points are values, but given your set of IDs you don't need to; an array would work well for the whole process.

#!/usr/local/bin/perl -w

use strict;

my @scores = (
  undef, undef, undef,       # skip IDs 0, 1, and 2
  7, 28, 19, 3, 36,
);

my @ids_by_score =
  sort { $scores[$b] <=> $scores[$a] }  # higher scores first
  3 .. $#scores;                        # IDs 3 to max ID

print "ID: Score\n";
for my $id (@ids_by_score) {
  printf "%2d: %5d\n", $id, $scores[$id];
}
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The main difference is that you get the list of IDs as 3 .. $#scores, instead of with keys(%scores) if it were a hash.