The weekly challenge 383 - Task 1: Similar List

 1 #!/usr/bin/env perl
 2 # https://theweeklychallenge.org/blog/perl-weekly-challenge-383/#TASK1
 3 #
 4 # Task 1: Similar List
 5 # ====================
 6 #
 7 # You are given three list of strings.
 8 #
 9 # Write a script to find out if the first two list are similar with the help
10 # the third list. The third list contains the similar words map.
11 #
12 ## Example 1
13 ##
14 ## Input: $list1 = ("great", "acting")
15 ##        $list2 = ("fine", "drama")
16 ##        $list3 = (["great", "fine"], ["acting", "drama"])
17 ## Output: true
18 #
19 ## Example 2
20 ##
21 ## Input: $list1 = ("apple", "pie")
22 ##        $list2 = ("banana", "pie")
23 ##        $list3 = (["apple", "peach"], ["peach", "banana"])
24 ## Output: false
25 #
26 ## Example 3
27 ##
28 ## Input: $list1 = ("perl4", "python")
29 ##        $list2 = ("raku", "python")
30 ##        $list3 = (["perl4", "perl5", "raku"])
31 ## Output: true
32 #
33 ## Example 4
34 ##
35 ## Input: $list1 = ("enjoy", "challenge")
36 ##        $list2 = ("love", "weekly", "challenge")
37 ##        $list3 = (["enjoy", "love"])
38 ## Output: false
39 #
40 ## Example 5
41 ##
42 ## Input: $list1 = ("fast", "car")
43 ##        $list2 = ("quick", "vehicle")
44 ##        $list3 = (["quick", "fast"], ["vehicle", "car"])
45 ## Output: true
46 #
47 ############################################################
48 ##
49 ## discussion
50 ##
51 ############################################################
52 #
53 # If both list1 and list2 have different lengths, they are not similar, so
54 # handle that case first. Then we return false for every index in the lists
55 # where the two values from the two lists don't map to similar words.
56 # In the end we know that for each index, the two elements map to similar
57 # words, so we can return true.
58 
59 use v5.36;
60 
61 sub similar_list($list1, $list2, $list3) {
62     say "Input: list1 = (" . join(", ", @$list1) . "),";
63     say "       list2 = (" . join(", ", @$list2) . "),";
64     say "       list3 = (" . join(", ", map {"[" . join(", ", @{$_}) . "]"} @$list3) . ")";
65 
66     return say "Output: false" unless scalar(@$list1) == scalar(@$list2);
67     my $last_index = scalar(@$list1) - 1;
68 
69     foreach my $i (0..$last_index) {
70         return say "Output: false" unless maps_the_same($list1->[$i], $list2->[$i], $list3);
71     }
72     say "Output: true";
73 }
74 
75 sub maps_the_same($elem1, $elem2, $list) {
76     return 1 if $elem1 eq $elem2;
77     foreach my $map (@$list) {
78         my $hash = {};
79         map { $hash->{$_} = 1, } @$map;
80         return 1 if $hash->{$elem1} && $hash->{$elem2};
81     }
82     return 0;
83 }
84 
85 similar_list(["great", "acting"], ["fine", "drama"], [["great", "fine"], ["acting", "drama"]]);
86 similar_list(["apple", "pie"], ["banana", "pie"], [["apple", "peach"], ["peach", "banana"]]);
87 similar_list(["perl4", "python"], ["raku", "python"], [["perl4", "perl5", "raku"]]);
88 similar_list(["enjoy", "challenge"], ["love", "weekly", "challenge"], [["enjoy", "love"]]);
89 similar_list(["fast", "car"], ["quick", "vehicle"], [["quick", "fast"], ["vehicle", "car"]]);
90