From 8968a5ff21e13aecd34c6a0697358cfe1fd30a4d Mon Sep 17 00:00:00 2001
From: boblied <boblied@gmail.com>
Date: Tue, 6 Oct 2020 07:26:56 -0500
Subject: Set up challenge 081

---
 .../bob-lied/perl/lib/CommonBaseString.pm          | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 challenge-081/bob-lied/perl/lib/CommonBaseString.pm

(limited to 'challenge-081/bob-lied/perl/lib/CommonBaseString.pm')

diff --git a/challenge-081/bob-lied/perl/lib/CommonBaseString.pm b/challenge-081/bob-lied/perl/lib/CommonBaseString.pm
new file mode 100644
index 0000000000..b67ecfa948
--- /dev/null
+++ b/challenge-081/bob-lied/perl/lib/CommonBaseString.pm
@@ -0,0 +1,39 @@
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# CommonBaseString.pm
+#=============================================================================
+# Copyright (c) 2020, Bob Lied
+#=============================================================================
+# Description:
+#=============================================================================
+
+package CommonBaseString;
+
+use strict;
+use warnings;
+use v5.30;
+
+use feature qw/ signatures /;
+no warnings qw/ experimental::signatures /;
+
+require Exporter;
+our @ISA = qw(Exporter);
+our @EXPORT = qw();
+our @EXPORT_OK = qw();
+
+sub new($class, $name1)
+{
+    $class = ref($class) || $class;
+    my $self = {
+        _name1 => $name1,
+    };
+    bless $self, $class;
+    return $self;
+}
+
+sub run($self)
+{
+    return undef;
+}
+
+1;
-- 
cgit 


From d0579dfc12bbc9d3878bd2aab8525e9b3140824b Mon Sep 17 00:00:00 2001
From: boblied <boblied@gmail.com>
Date: Fri, 9 Oct 2020 15:34:05 -0500
Subject: Solutions for PWC 081

---
 .../bob-lied/perl/lib/CommonBaseString.pm          | 48 ++++++++++++++++++++--
 1 file changed, 44 insertions(+), 4 deletions(-)

(limited to 'challenge-081/bob-lied/perl/lib/CommonBaseString.pm')

diff --git a/challenge-081/bob-lied/perl/lib/CommonBaseString.pm b/challenge-081/bob-lied/perl/lib/CommonBaseString.pm
index b67ecfa948..4c6f98901c 100644
--- a/challenge-081/bob-lied/perl/lib/CommonBaseString.pm
+++ b/challenge-081/bob-lied/perl/lib/CommonBaseString.pm
@@ -19,21 +19,61 @@ no warnings qw/ experimental::signatures /;
 require Exporter;
 our @ISA = qw(Exporter);
 our @EXPORT = qw();
-our @EXPORT_OK = qw();
+our @EXPORT_OK = qw(commonPrefix);
 
-sub new($class, $name1)
+sub new($class, $a, $b)
 {
     $class = ref($class) || $class;
     my $self = {
-        _name1 => $name1,
+        _a => $a,
+        _b => $b,
     };
     bless $self, $class;
     return $self;
 }
 
+# 
+sub commonPrefix($s, $t)
+{
+    my @s1 = split("", $s);
+    my @s2 = split("", $t);
+    my $prefix = "";
+    my @possiblePrefixes = ();
+
+    while ( @s1 && @s2 && ($s = shift @s1) eq ($t = shift @s2) )
+    {
+        $prefix .= $s;
+        push @possiblePrefixes, $prefix;
+    }
+    return \@possiblePrefixes;
+}
+
 sub run($self)
 {
-    return undef;
+    my ($A, $B) = @{$self}{qw(_a _b)};
+    my ($lenA, $lenB) = ( length($A), length($B) );
+    my @thisWorks = ();
+
+    my $prefixes = commonPrefix($A, $B);
+
+    for my $prefix ( @$prefixes )
+    {
+        my $lenP = length($prefix);
+        # Only prefixes that can be repeated to the length of both strings
+        # are candidates.
+        next unless $lenA % $lenP == 0;
+        next unless $lenB % $lenP == 0;
+
+        # Number of repetitions required for each string.
+        my $repA = $lenA / $lenP;
+        my $repB = $lenB / $lenP;
+
+        my $buildsA = ( ($prefix x $repA) eq $A );
+        my $buildsB = ( ($prefix x $repB) eq $B );
+        push @thisWorks, $prefix if ( $buildsA && $buildsB );
+    }
+
+    return \@thisWorks;
 }
 
 1;
-- 
cgit