- Added template for Challenge 82.

1 files changed, 162 insertions, 0 deletions

diff --git a/challenge-082/andinus/README b/challenge-082/andinus/README
new file mode 100644
index 0000000000..13354ca364
--- /dev/null
+++ b/challenge-082/andinus/README
@@ -0,0 +1,162 @@
+                            ━━━━━━━━━━━━━━━
+                             CHALLENGE 081
+
+                                Andinus
+                            ━━━━━━━━━━━━━━━
+
+
+Table of Contents
+─────────────────
+
+1. Task 1 - Common Base String
+.. 1. Perl
+2. Task 2 - Frequency Sort
+.. 1. Perl
+
+
+
+
+
+1 Task 1 - Common Base String
+═════════════════════════════
+
+  You are given 2 strings, `$A' and `$B'.
+
+  Write a script to find out common base strings in `$A' and `$B'.
+
+        A substring of a string $S is called base string if
+        repeated concatenation of the substring results in the
+        string.
+
+
+1.1 Perl
+────────
+
+  • Program: <file:perl/ch-1.pl>
+
+  We will break `$A' & check if any subset of `$A' join to make `$B'. To
+  speed up the process we only break `$A' by common divisors of both
+  `$A' & `$B'.
+
+  I assume that the length of `$B' is greater than `$A' in later parts
+  so we make sure that it's true.
+  ┌────
+  │ my $A = shift @ARGV;
+  │ my $B = shift @ARGV;
+  │
+  │ # We assume length($B) is greater than length($A).
+  │ unless (length($B) > length($A)) {
+  │     my $tmp = $A;
+  │     $A = $B;
+  │     $B = $tmp;
+  │ }
+  └────
+
+  If the strings have different sets of characters then common base
+  string cannot exists so we exit early.
+  ┌────
+  │ # Check if common base string is even possible.
+  │ my (%chars_in_A, %chars_in_B);
+  │ $chars_in_A{$_} = 1 foreach split //, $A;
+  │ $chars_in_B{$_} = 1 foreach split //, $B;
+  │ foreach my $char (sort keys %chars_in_A) {
+  │     last if exists $chars_in_B{$char} ;
+  │     print "No common base string.\n" and exit 0
+  │ }
+  └────
+
+  Get all the common divisors of `$A' & `$B'.
+  ┌────
+  │ # Get all common divisors.
+  │ my %divisors_of_A = divisors(length($A));
+  │ my %divisors_of_B = divisors(length($B));
+  │ my @common_divisors;
+  │ foreach my $num (sort { $a <=> $b } keys %divisors_of_A) {
+  │     push @common_divisors, $num
+  │         if exists $divisors_of_B{$num};
+  │ }
+  │
+  │ # Returns all divisors of a number.
+  │ sub divisors {
+  │     my $n = shift @_;
+  │     my %divisors;
+  │     foreach my $i ( 1 ... $n){
+  │         if ($n % $i == 0) {
+  │             $divisors{$i} = 1;
+  │         }
+  │     }
+  │     return %divisors;
+  │ }
+  └────
+
+  We check if any subset of `$A' joins to make `$B'.
+  ┌────
+  │ my @common;
+  │
+  │ foreach my $num (@common_divisors){
+  │     my $tmp;
+  │     my $base = substr($A, 0, $num);
+  │     foreach (1 ... length($B) / $num) {
+  │         $tmp .= $base;
+  │     }
+  │     push @common, $base if $tmp eq $B;
+  │ }
+  │
+  │ print "No common base string.\n" and exit 0
+  │     unless scalar @common;
+  │ print join(', ', @common), "\n";
+  └────
+
+
+2 Task 2 - Frequency Sort
+═════════════════════════
+
+  You are given file named input.
+
+  Write a script to find the frequency of all the words.
+
+  It should print the result as first column of each line should be the
+  frequency of the the word followed by all the words of that frequency
+  arranged in lexicographical order. Also sort the words in the
+  ascending order of frequency.
+
+  For the sake of this task, please ignore the following in the input
+  file: `. " ( ) , 's --'
+
+
+2.1 Perl
+────────
+
+  • Program: <file:perl/ch-2.pl>
+
+  Swap unwanted characters with a space.
+  ┌────
+  │ my $file = path(shift @ARGV)->slurp;
+  │
+  │ $file =~ s/(--|'s)/ /g;
+  │ $file =~ s/[."(),]+/ /g;
+  │ $file =~ s/  / /g;
+  │ $file =~ s/\n/ /g;
+  └────
+
+  Get frequency of each word.
+  ┌────
+  │ my %words;
+  │ foreach my $word (split / /, $file) {
+  │     $words{$word} = 1 and next unless exists $words{$word};
+  │     $words{$word}++;
+  │ }
+  └────
+
+  Format the output.
+  ┌────
+  │ my %out;
+  │ foreach my $word (sort keys %words) {
+  │     my $freq = $words{$word};
+  │     push @{$out{$freq}}, $word;
+  │ }
+  │
+  │ foreach my $freq (sort { $a <=> $b} keys %out) {
+  │     print "$freq ", join(' ', @{$out{$freq}}, "\n");
+  │ }
+  └────