Merge pull request #6195 from LubosKolouch/master

Challenge 167 Task 1 Perl

1 files changed, 52 insertions, 0 deletions

diff --git a/challenge-167/lubos-kolouch/perl/ch-1.pl b/challenge-167/lubos-kolouch/perl/ch-1.pl
new file mode 100644
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+++ b/challenge-167/lubos-kolouch/perl/ch-1.pl
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+use strict;
+use warnings;
+use Math::Prime::Util qw(is_prime next_prime);
+
+sub is_circular_prime {
+    my $prime = shift;
+
+    my $digits = length($prime);
+
+    for my $i ( 0 .. $digits - 1 ) {
+        return 0 unless is_prime($prime);
+        my $digit = substr( $prime, 0, 1 );
+        $prime = substr( $prime, 1, $digits - 1 ) . $digit;
+    }
+
+    return 1;
+}
+
+sub generate_primes {
+    my $limit = shift;
+
+    my @primes;
+    my $prime = next_prime(100);
+
+    while ( scalar @primes < $limit ) {
+        push @primes, $prime if is_circular_prime($prime);
+        $prime = next_prime($prime);
+    }
+
+    return \@primes;
+}
+
+use Test::More;
+
+is( is_circular_prime(2),   1, '2 is a circular prime' );
+is( is_circular_prime(3),   1, '3 is a circular prime' );
+is( is_circular_prime(11),  1, '11 is a circular prime' );
+is( is_circular_prime(13),  1, '13 is a circular prime' );
+is( is_circular_prime(57),  0, '57 not a circular prime' );
+is( is_circular_prime(197), 1, '197 is a circular prime' );
+
+# Note that the example given on the challenge is wrong according to
+# https://oeis.org/A068652
+
+is_deeply(
+    generate_primes(10),
+    [ 113, 131, 197, 199, 311, 337, 373, 719, 733, 919 ],
+
+    'Generate primes'
+);
+
+done_testing();