use warnings;
use strict;
use Data::Dump;

my @trip = ("Chicago", "Saint Looey", "Joplin", "OKC", "Amarillo",
	"Gallup", "Flagstaff", "Winona", "Kingman", "Barstow",
	"San Bernandino", "LA");

my %cities = ( "Amarillo" => { state => "TX" },
	"Barstow" => { state => "CA" }, "Chicago" => { state => "IL" },
	"Flagstaff" => { state => "AZ" }, "Gallup" => { state => "TX" },
	"Joplin" => { state => "MO" }, "Kingman" => { state => "AZ" },
	"LA" => { state => "CA" }, "OKC" => { state => "OK" },
	"Saint Looey" => { state => "MO" },
	"San Bernandino" => { state => "CA" },
	"Winona" => { state => "AZ" }, );

for my $i (0..$#trip-1) {
	my ($from,$to) = @trip[$i,$i+1];
	print "$from, $cities{$from}{state} to $to, $cities{$to}{state}",
		$cities{$from}{state} ne $cities{$to}{state}
			? " - Mann Act!" : (), "\n";
}

print "\n##### Alternative #####\n";

$cities{$_}{city} = $_ for keys %cities;
$_ = $cities{$_}//die("bad city $_") for @trip;
dd \%cities, \@trip;

for my $i (0..$#trip-1) {
	my ($from,$to) = @trip[$i,$i+1];
	print "$from->{city}, $from->{state} to $to->{city}, "
		."$to->{state}", $from->{state} ne $to->{state}
			? " - Mann Act!" : (), "\n";
}

##</code><code>##

Chicago, IL to Saint Looey, MO - Mann Act!
Saint Looey, MO to Joplin, MO
Joplin, MO to OKC, OK - Mann Act!
OKC, OK to Amarillo, TX - Mann Act!
Amarillo, TX to Gallup, TX
Gallup, TX to Flagstaff, AZ - Mann Act!
Flagstaff, AZ to Winona, AZ
Winona, AZ to Kingman, AZ
Kingman, AZ to Barstow, CA - Mann Act!
Barstow, CA to San Bernandino, CA
San Bernandino, CA to LA, CA

##### Alternative #####
do {
  my $a = {
    "Amarillo"       => { city => "Amarillo", state => "TX" },
    "Barstow"        => { city => "Barstow", state => "CA" },
    "Chicago"        => { city => "Chicago", state => "IL" },
    "Flagstaff"      => { city => "Flagstaff", state => "AZ" },
    "Gallup"         => { city => "Gallup", state => "TX" },
    "Joplin"         => { city => "Joplin", state => "MO" },
    "Kingman"        => { city => "Kingman", state => "AZ" },
    "LA"             => { city => "LA", state => "CA" },
    "OKC"            => { city => "OKC", state => "OK" },
    "Saint Looey"    => { city => "Saint Looey", state => "MO" },
    "San Bernandino" => { city => "San Bernandino", state => "CA" },
    "Winona"         => { city => "Winona", state => "AZ" },
  };
  (
    $a,
    [
      $a->{"Chicago"},
      $a->{"Saint Looey"},
      $a->{"Joplin"},
      $a->{"OKC"},
      $a->{"Amarillo"},
      $a->{"Gallup"},
      $a->{"Flagstaff"},
      $a->{"Winona"},
      $a->{"Kingman"},
      $a->{"Barstow"},
      $a->{"San Bernandino"},
      $a->{"LA"},
    ],
  );
}
Chicago, IL to Saint Looey, MO - Mann Act!
Saint Looey, MO to Joplin, MO
Joplin, MO to OKC, OK - Mann Act!
OKC, OK to Amarillo, TX - Mann Act!
Amarillo, TX to Gallup, TX
Gallup, TX to Flagstaff, AZ - Mann Act!
Flagstaff, AZ to Winona, AZ
Winona, AZ to Kingman, AZ
Kingman, AZ to Barstow, CA - Mann Act!
Barstow, CA to San Bernandino, CA
San Bernandino, CA to LA, CA

##</code><code>##

use warnings;
use strict;
use Data::Dump;
use List::Util 'pairs';
use List::MoreUtils 'mesh';

my @trip = ("Chicago", "Saint Looey", "Joplin", "OKC", "Amarillo",
	"Gallup", "Flagstaff", "Winona", "Kingman", "Barstow",
	"San Bernandino", "LA");
my @states = ("IL", "MO", "MO", "OK", "TX", "TX",  "AZ", "AZ",
	"AZ", "CA", "CA", "CA" );

my @legs = map {@trip[$_,$_+1]} 0..$#trip-1;
printf "%15s to %-15s\n", $_->[0], $_->[1] for pairs @legs;

my %info;
$info{$_->[0]}{state} = $_->[1] for pairs mesh @trip, @states;
dd \%info;

__END__
        Chicago to Saint Looey    
    Saint Looey to Joplin         
         Joplin to OKC            
            OKC to Amarillo       
       Amarillo to Gallup         
         Gallup to Flagstaff      
      Flagstaff to Winona         
         Winona to Kingman        
        Kingman to Barstow        
        Barstow to San Bernandino 
 San Bernandino to LA             
{
  "Amarillo"       => { state => "TX" },
  "Barstow"        => { state => "CA" },
  "Chicago"        => { state => "IL" },
  "Flagstaff"      => { state => "AZ" },
  "Gallup"         => { state => "TX" },
  "Joplin"         => { state => "MO" },
  "Kingman"        => { state => "AZ" },
  "LA"             => { state => "CA" },
  "OKC"            => { state => "OK" },
  "Saint Looey"    => { state => "MO" },
  "San Bernandino" => { state => "CA" },
  "Winona"         => { state => "AZ" },
}