Merge pull request #240 from yzhernand/ch-012-yozen

Added solutions by Yozen Hernandez for challenges 1 and 2 for week 12

3 files changed, 99 insertions, 0 deletions

diff --git a/challenge-012/yozen-hernandez/blog.txt b/challenge-012/yozen-hernandez/blog.txt
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+https://yzhernand.github.io/posts/perl-weekly-challenge-12/
\ No newline at end of file
diff --git a/challenge-012/yozen-hernandez/perl5/ch-1.pl b/challenge-012/yozen-hernandez/perl5/ch-1.pl
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+++ b/challenge-012/yozen-hernandez/perl5/ch-1.pl
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+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw(say state);
+use Carp;
+
+# The numbers formed by adding one to the products of the smallest primes are
+# called the Euclid Numbers (see wiki). Write a script that finds the smallest
+# Euclid Number that is not prime. This challenge was proposed by Laurent
+# Rosenfeld.
+
+sub is_prime {
+    my $n = shift;
+
+    return 0 if grep { $n % $_ == 0 } ( 2 .. sqrt($n) );
+
+    return 1;
+}
+
+sub prime_iterator {
+    my $n = 1;
+    return sub {
+        1 until is_prime ++$n;
+        return $n;
+        }
+}
+
+sub euclid_prime_iterator {
+    my $prime_iter = prime_iterator();
+    my $prime_prod = 1;
+    return sub {
+        $prime_prod *= $prime_iter->();
+        return $prime_prod + 1;
+        }
+}
+
+# scen = Smallest Composite Euclid Number
+my $iter = euclid_prime_iterator();
+my $scen = 0;
+$scen = $iter->() until ( is_prime($scen) == 0 );
+say $scen;
diff --git a/challenge-012/yozen-hernandez/perl5/ch-2.pl b/challenge-012/yozen-hernandez/perl5/ch-2.pl
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+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use Carp;
+
+# Write a script that finds the common directory path, given a collection of
+# paths and directory separator. For example, if the following paths are
+# supplied.
+
+sub find_common_path {
+    my ( $path_sep, $paths_ref ) = @_;
+    my @common_path;
+
+    for my $p ( @{$paths_ref} ) {
+        my @split_p = split /$path_sep/, $p;
+        unless (@common_path) {
+            @common_path = @split_p;
+            next;
+        }
+
+        if ( @split_p < @common_path ) {
+            @common_path = @common_path[ 0 .. @split_p - 1 ];
+        }
+
+        for my $i ( 0 .. @common_path - 1 ) {
+
+            # Stop processing this path as soon as we encounter
+            # a directory not seen before
+            if ( $split_p[$i] ne $common_path[$i] ) {
+
+                # Save only the so-far shared path.
+                # The array will always have one element
+                # thanks to the fact that the first separator
+                # is also the first character.
+                @common_path = @common_path[ 0 .. $i - 1 ];
+                last;
+            }
+        }
+
+        return ('') if ( @common_path == 1 && $common_path[0] eq '' );
+    }
+
+    return @common_path;
+}
+
+my @path_list = qw(/a/b/c/d
+    /a/b/cd
+    /a/b/cc
+    /a/b/c/d/e);
+
+my $path_sep = "/";
+my @common_path = find_common_path( $path_sep, \@path_list );
+
+say "Common path is: '", join( $path_sep, @common_path ), "'";