gistfile1.pl

#! /usr/bin/perl -w

use strict;
use warnings;
use feature 'say';
use Data::Dump;

my %total_bytes;
while (<>) {
  my ($source,$destination,$bytes) = split;
  $total_bytes{$source}{$destination} += $bytes;
}

say dd(%total_bytes);
say 'Hello';

### DATA FILE
#professor.hut gilligan.crew.hut 1250
#professor.hut lovey.howell.hut 910
#thurston.howell.hut lovey.howell.hut 1250
#professor.hut lovey.howell.hut 450
#ginger.girl.hut professor.hut 1218
#ginger.girl.hut maryann.girl.hut 199