The weekly challenge 305 - Task 2: Alien Dictionary

 1 #!/usr/bin/env perl
 2 # https://theweeklychallenge.org/blog/perl-weekly-challenge-305/#TASK2
 3 #
 4 # Task 2: Alien Dictionary
 5 # ========================
 6 #
 7 # You are given a list of words and alien dictionary character order.
 8 #
 9 # Write a script to sort lexicographically the given list of words based on the
10 # alien dictionary characters.
11 #
12 ## Example 1
13 ##
14 ## Input: @words = ("perl", "python", "raku")
15 ##        @alien = qw/h l a b y d e f g i r k m n o p q j s t u v w x c z/
16 ## Output: ("raku", "python", "perl")
17 #
18 ## Example 2
19 ##
20 ## Input: @words = ("the", "weekly", "challenge")
21 ##        @alien = qw/c o r l d a b t e f g h i j k m n p q s w u v x y z/
22 ## Output: ("challenge", "the", "weekly")
23 #
24 ############################################################
25 ##
26 ## discussion
27 ##
28 ############################################################
29 #
30 # We transliterate all words to their conjugate word in the transliterated
31 # namespace, then we can sort alphabetically. The we transliterate the sorted
32 # words back to the original words.
33 
34 use strict;
35 use warnings;
36 
37 alien_dictionary( ["perl", "python", "raku"], qw/h l a b y d e f g i r k m n o p q j s t u v w x c z/ );
38 alien_dictionary( ["the", "weekly", "challenge"], qw/c o r l d a b t e f g h i j k m n p q s w u v x y z/ );
39 
40 sub alien_dictionary {
41    my ($words, @alien) = @_;
42    print "Input: (" . join(", ", @$words) . ")\n";
43    print "       qw/" . join(" ", @alien) . "/\n";
44    my $alien = join("",@alien);
45    my @tmp = ();
46    foreach my $w (@$words) {
47       eval "\$w =~ tr/a-z/$alien/;";
48       push @tmp, $w;
49    }
50    my @sorted = sort @tmp;
51    @tmp = ();
52    foreach my $w (@sorted) {
53       eval "\$w =~ tr /$alien/a-z/;";
54       push @tmp, $w;
55    }
56    print "Output: (" . join(", ", @tmp) . ")\n";
57 }