How would you do this without a computer?

Once you have written down the steps to do this without a computer, write these steps in Perl.

Please, do not treat this site as a code writing service. We expect you to do your work yourself.

You can improve the quality of answers you get by showing runnable code which sets up the data in a simple way. For example, instead of a comment or pseudocode, just initialize your data with dummy data:

my @nodelist = ("dummy1", "dummy2", "dummy3", "dummy4");
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