2 files changed, 47 insertions, 0 deletions
diff --git a/challenge-204/wlmb/perl/ch-1.pl b/challenge-204/wlmb/perl/ch-1.pl
new file mode 100755
index 0000000000..66cc937e71
--- /dev/null
+++ b/challenge-204/wlmb/perl/ch-1.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 204
+# Task 1:  Monotonic Array
+#
+# See https://wlmb.github.io/2023/02/13/PWC204/#task-1-monotonic-array
+use v5.36;
+die <<~"FIN" unless @ARGV;
+    Usage: $0 N1 [N2...]
+    to test if the sequence N1 N2... is monotonic
+    FIN
+my @orig=@ARGV;
+my $current=shift;
+my ($increasing, $decreasing);
+for(@ARGV){
+    $_>$current and $increasing=1;
+    $_<$current and $decreasing=1;
+    last if $increasing and $decreasing; # shortcut if non monotonic
+    $current=$_;
+}
+my ($result, $reason)=
+    $increasing && $decreasing?(0, "Non-monotonic"):
+    $increasing               ?(1, "Non-decreasing"):
+    $decreasing               ?(1, "Non-increasing"):
+    (1, "Constant");
+say join " ", @orig, "->", $result, $reason;
diff --git a/challenge-204/wlmb/perl/ch-2.pl b/challenge-204/wlmb/perl/ch-2.pl
new file mode 100755
index 0000000000..af92096064
--- /dev/null
+++ b/challenge-204/wlmb/perl/ch-2.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 204
+# Task 2:  Reshape Matrix
+#
+# See https://wlmb.github.io/2023/02/13/PWC204/#task-2-reshape-matrix
+use v5.36;
+use PDL;
+die <<~"FIN" unless @ARGV==3;
+    Usage: $0 M r c
+    to convert matrix M (a string using PDL's notation)
+    to a matrix with r rows, c columns
+    FIN
+my $M=pdl shift;
+my ($rows, $cols)=@ARGV;
+my $nelem=$M->nelem; # total number of elements
+my $desired=$rows*$cols;
+say("$M cannot be reshaped to $rows rows and $cols columns: 0"), exit
+    unless $desired==$nelem;
+my $N=$M->copy;
+$N->reshape($cols) if $rows==1;        # 1D row vector
+$N->reshape($cols, $rows) if $rows!=1; #2D matrix
+say "$M as $rows x $cols matrix becomes $N"