my %location;
@location{@links} = @urls;
print $_, ': ', $location{$_}, $/ for sort keys %location;

##</code><code>##

my @locations = map {[$urls[$_], $links[$_]]} 0 .. $#urls;
print join(': ', @$_), $/ for sort {$a->[1] cmp $b->[1]} @locations;