Week 154: Perl solutions.

2 files changed, 101 insertions, 0 deletions

diff --git a/challenge-154/abigail/perl/ch-1.pl b/challenge-154/abigail/perl/ch-1.pl
new file mode 100644
index 0000000000..e60d3df7a1
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+++ b/challenge-154/abigail/perl/ch-1.pl
@@ -0,0 +1,31 @@
+#!/opt/perl/bin/perl
+
+use 5.032;
+
+use strict;
+use warnings;
+no  warnings 'syntax';
+
+use experimental 'signatures';
+use experimental 'lexical_subs';
+
+#
+# See https://theweeklychallenge.org/blog/perl-weekly-challenge-154
+#
+
+#
+# Run as: perl ch-1.pl < input-file
+#
+
+#
+# Create a hash with all possible permutation as key, delete the
+# ones from the input, print what remains. We make use of the fact
+# that "PERL" doesn't have duplicate letters.
+#
+
+my           %all;
+             @all {grep {!/(.).*\g{1}/} glob "{P,E,R,L}" x 4} = ();
+delete       @all {map {chop; $_} <>};
+say for keys %all;
+
+__END__
diff --git a/challenge-154/abigail/perl/ch-2.pl b/challenge-154/abigail/perl/ch-2.pl
new file mode 100644
index 0000000000..4a691a2da6
--- /dev/null
+++ b/challenge-154/abigail/perl/ch-2.pl
@@ -0,0 +1,70 @@
+#!/opt/perl/bin/perl
+
+use 5.032;
+
+no strict;
+no warnings;
+
+use experimental 'signatures';
+use experimental 'lexical_subs';
+
+#
+# See https://theweeklychallenge.org/blog/perl-weekly-challenge-154
+#
+
+#
+# Run as: perl ch-2.pl
+#
+
+#
+# Seriously? If you cannot come with anything remotely new, just shut
+# down the weekly challenge.
+#
+# Once again, we're asked to
+#   1) produce the first N numbers of an OEIS sequence, with N fixed
+#   2) a trivial recurrence 
+#   3) filter on/use prime numbers
+#
+# We did 1) recently in challenge 153-1, 150-2, 148-1, 147-1, 144-1, 133-2, etc
+#
+# We did 2) recently in challenge 150-1, 149-1, 147-2, 144-2, 136-2, etc
+#
+# We did 3) recently in challenge 150-2, 147-1, 146-1, 144-1, 141-1, etc
+#
+
+#
+# This is just sequence A100891
+#
+
+#
+# To find out whether a number is prime, we could use 
+#
+# Math::Util::Prime, but we have seen this a gazillion times recently
+# in the Colins weekly review. We could use trial division, but we
+# have seen that one a gazillion times in the same review as well.
+# Same with using a sieve.
+#
+# It'll be fucking boring to see the same copy and pasted code over
+# and over again.
+#
+# So, today, we'll do something different. To check if a number N is prime,
+# we randomly pick a number d, 2 <= d < N, and see if it divides N. If it
+# does, N is not prime. If not, we pick a different number, until we either
+# have found N to be composite, or we have picked all N - 3 different numbers.
+#
+# We also won't be generating the Padovan number using a recurrence.
+# Instead, we'll just count upwards, and check if we encountered a 
+# Padovan number.
+#
+# Efficient? No, not at all. But better than falling asleep reading the
+# same solutioons we seen many times before over and over again.
+#
+# You might get a cup of tea when running this program. Better, get two cups.
+#
+# Oh, and we cram the entire program in just three lines. Just to make the
+# challenge a bit interesting.
+#
+
+sub _($n){%;=();while(%;<$n-2){$n%($;=2+int(rand($n-2)))||return;$;{$;}=1}1}
+($-,$:,@:)=(10,(1)x3,2);
+++$:&&($:==$:[-2]+$:[-3])&&(push@:,$:)&&_($:)&&say($:)&&$---while$-