Merge pull request #244 from shardiwal/shardiwal_012

Shardiwal 012

3 files changed, 103 insertions, 0 deletions

diff --git a/challenge-012/shardiwal/README b/challenge-012/shardiwal/README
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@@ -0,0 +1 @@
+Solution by Rakesh Kumar Shardiwal
diff --git a/challenge-012/shardiwal/perl5/ch-1.pl b/challenge-012/shardiwal/perl5/ch-1.pl
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+++ b/challenge-012/shardiwal/perl5/ch-1.pl
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+#!/usr/bin/perl
+
+use warnings;
+use strict;
+use feature qw(say);
+
+# 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.
+
+say scan_not_prime_euclid_number();
+
+sub scan_not_prime_euclid_number {
+	my $number = 1;
+	my $eucid_number;
+	while ( not $eucid_number ) {
+		$eucid_number = get_euclid_number($number);
+		$number++;
+	}
+	return $eucid_number;
+}
+
+sub get_euclid_number {
+	my $num = shift;
+	my $product = prime_product($num);
+	my $eucid_number = $product + 1;
+	return if is_prime($eucid_number);
+	# Euclid Number that is not prime.
+	return $eucid_number;
+}
+
+sub prime_product {
+	my $num     = shift;
+	my $product = 1;
+	map { $product *= $_ if is_prime($_); } ( 1 .. $num );
+	return $product;
+}
+
+sub is_prime {
+	my $number   = shift;
+	return 0 if grep { $number % $_ == 0 } ( 2 .. sqrt($number) );
+	return 1;
+}
diff --git a/challenge-012/shardiwal/perl5/ch-2.pl b/challenge-012/shardiwal/perl5/ch-2.pl
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+++ b/challenge-012/shardiwal/perl5/ch-2.pl
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+#!/usr/bin/perl
+
+use warnings;
+use strict;
+use feature qw(say);
+use Data::Dumper;
+
+# 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.
+
+my @path_list = qw(
+	/a/b/c/d
+	/a/b/cd
+	/a/b/cc
+	/a/b/c/d/e
+);
+
+say find_common_path( \@path_list, "/" );
+
+sub find_common_path {
+	my ( $path_list, $separator ) = @_;
+	my $path_mapping = common_path_mapping( $path_list, $separator );
+	my $common_path;
+	my $uses = 0;
+	while ( my ($path, $used) = each %$path_mapping ) {
+		my $used_no_of_times = scalar @$used;
+		if ( $used_no_of_times > $uses ){
+			$uses = $used_no_of_times;
+			$common_path = $path;
+		}
+	}
+	return $separator . $common_path;
+}
+
+sub common_path_mapping {
+	my ( $path_list, $separator ) = @_;
+	my %paths;
+	map {
+		my $line = $_;
+		my $dirs = _get_directories_in_path( $line, $separator );
+		my $i = 1;
+		foreach my $dir ( @$dirs ) {
+			next unless $dirs->[$i];
+			my $path_in_chunk = join( $separator, @$dirs[0..$i] );
+			push( @{ $paths{$path_in_chunk} }, $line);
+			$i++;
+		}
+	} @$path_list;
+	return \%paths;
+}
+
+sub _get_directories_in_path {
+	my ( $path, $separator ) = @_;
+	my @dirs = split /$separator/, $path;
+	shift @dirs;
+	return \@dirs;
+}
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