Browsing reddit the other day, I discovered this thread about a programming puzzle on the Spotify jobs website. Doubt I'm qualified for a job at Spotify, but I like puzzles well enough. Here's my crack at a solution in Perl:

#!/usr/bin/env perl

use strict;
use warnings;
use List::MoreUtils qw/uniq/;
use feature qw/state say/;

my $friend_id = 1009;
my %seen;
my @teams;
my @reps;

while (<>) {
  chomp;
  state $count = 0;
  if($count > 0) {
    my $pair = make_pair($_);
    $seen{$pair->[0]}++;
    $seen{$pair->[1]}++;
    push @teams, $pair
  }
  $count++;
}

LINE: for my $pair (@teams) {
  my ($first, $second) = ($pair->[0], $pair->[1]);
  if($seen{$first} >= 2) {
    push @reps, $first;
    next LINE;
  } 
  elsif($seen{$second} >= 2) {
    push @reps, $second;
    next LINE;
  }
  else {
    $second == 1009
    ? push @reps, $second
    : $first == 1009
    ? push @reps, $first
    : push @reps, $first;
  }
}

my @result = uniq @reps;
say scalar @result;
say for @result;

sub make_pair {
  ## Str -> ArrayRef
  my $s = shift;
  my @pair = split / /, $s;
  \@pair;
}

[download]

Anyone have a better way to do it? I'm sure there's plenty of fat to be trimmed here. :-)

My next move is to write a small program that generates the desired input files so I can do some more thorough testing; just thought it'd be fun to get some feedback from other folks on my perling.

-- C-x C-c

In reply to Perl Solution to Spotify Programming Puzzle by ::rml::

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