Merge pull request #811 from dcw803/master

two very straighforward problems this week.. no particular subtlety..

3 files changed, 59 insertions, 19 deletions

diff --git a/challenge-030/duncan-c-white/README b/challenge-030/duncan-c-white/README
index b00307c5eb..2d973d0053 100644
--- a/challenge-030/duncan-c-white/README
+++ b/challenge-030/duncan-c-white/README
@@ -1,23 +1,13 @@
-Challenge 1: "Write a script to demonstrate brace expansion. For example,
-script would take command line argument Perl {Daily,Weekly,Monthly,Yearly}
-Challenge and should expand it and print like below:
+Challenge 1: "Write a script to list dates for Sunday Christmas between
+	      2019 and 2100. For example, 25 Dec 2022 is Sunday."
 
-  Perl Daily Challenge
-  Perl Weekly Challenge
-  Perl Monthly Challenge
-  Perl Yearly Challenge
+My notes: Very well defined, another job for Date::Manip or Date::Simple..
 
-My notes: Nested braces may be slightly tricky, first I tried a recursive
-function to find and expand the innermost {}, but that produced the
-right output in a weird order, with duplicates.
-Instead, try a state machine to track the locations of the outer level
-elements {,}.  Extract $before, $after and an array of alternatives @alt,
-then recombine them, until there are no { left.
 
+Challenge 2: "Write a script to print all possible series of 3 positive
+	      numbers, where in each series at least one of the number is even and
+	      sum of the three numbers is always 12. For example, 3,4,5."
 
-Challenge 2: "Write a script to demonstrate calling a C function. It
-could be any user defined or standard C function."
-
-My notes: Hmm, either XS or Inline::C.  I've never used either:-)
-Wrote simple sqrt routine (algorithm: squaring the rectangle) in C,
-wrote the same in Perl, then used Benchmark to benchmark both versions.
+My notes: Well defined, looks straightforward by brute forcish search (with
+the third number in the sequence being fixed as 12-first-second of course,
+so only two degrees of freedom).
diff --git a/challenge-030/duncan-c-white/perl5/ch-1.pl b/challenge-030/duncan-c-white/perl5/ch-1.pl
new file mode 100755
index 0000000000..2b44f2522c
--- /dev/null
+++ b/challenge-030/duncan-c-white/perl5/ch-1.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/perl
+#
+# Challenge 1: "Write a script to list dates for Sunday Christmas between
+#	      2019 and 2100. For example, 25 Dec 2022 is Sunday."
+#
+# My notes: Very well defined, another job for Date::Manip or Date::Simple..
+# 
+
+use v5.10;	# to get "say"
+use strict;
+use warnings;
+use Date::Simple qw(date today);
+
+die "Usage: ch-1.pl [STARTYEAR [ENDYEAR]]\n" if @ARGV > 2;
+my $startyear = shift // 2019;
+my $endyear = shift // 2100;
+
+foreach my $year ($startyear..$endyear)
+{
+	my $dstr = "$year-12-25";
+	my $dow = date( $dstr )->day_of_week;
+	say $dstr if $dow == 0;
+}
diff --git a/challenge-030/duncan-c-white/perl5/ch-2.pl b/challenge-030/duncan-c-white/perl5/ch-2.pl
new file mode 100755
index 0000000000..7dab1e155c
--- /dev/null
+++ b/challenge-030/duncan-c-white/perl5/ch-2.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+#
+# Challenge 2: "Write a script to print all possible series of 3 positive
+# 	      numbers, where in each series at least one of the number is even
+# 	      and sum of the three numbers is always 12. For example, 3,4,5."
+# 
+# My notes: Well defined, looks straightforward by brute forcish search (with
+# the third number in the sequence being fixed as 12-first-second of course,
+# so only two degrees of freedom).
+#
+
+use v5.10;	# for "say"
+use strict;
+use warnings;
+#use Data::Dumper;
+
+
+foreach my $first (1..10)
+{
+	foreach my $second (1..11-$first)
+	{
+		my $third = 12 - $first - $second;
+		next if $third<1;
+		next if $first%2==1 && $second%2==1 && $third%2==1;
+		say "$first-$second-$third";
+	}
+}