From 5e9b9caf403ffb066d900d120dcaf409dc1c4e7a Mon Sep 17 00:00:00 2001
From: Luis Mochan <mochan@fis.unam.mx>
Date: Mon, 15 Sep 2025 13:42:45 -0600
Subject: Error checking

---
 challenge-339/wlmb/perl/ch-1.pl | 21 +++++++++++----------
 challenge-339/wlmb/perl/ch-2.pl |  4 ++--
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/challenge-339/wlmb/perl/ch-1.pl b/challenge-339/wlmb/perl/ch-1.pl
index 4a51a15470..77066bffd6 100755
--- a/challenge-339/wlmb/perl/ch-1.pl
+++ b/challenge-339/wlmb/perl/ch-1.pl
@@ -15,17 +15,18 @@ die <<~"FIN" unless @ARGV;
     FIN
 for(@ARGV){
     try {
-	my $in=pdl($_);
-	my $products=$in*$in(*1);
-	my $diffs=$products-$products(*1,*1);  # Xi*Xj-Xk*Xl
-	my ($i, $j, $k, $l) = $diffs->ndcoords->mv(0,-1)->dog; #coordinates into ndarray $diffs
-	$diffs=$diffs->where(
-	    ($i!=$j)&($i!=$k)&($i!=$l)
-	    &($j!=$k)&($j!=$l)
-	    &($k!=$l));  # select elements with no repeating coordinates
-	say "$_ -> ", $diffs->max;
+        my $in=pdl($_);
+	die "Expected four or more numbers" unless $in->dim(0)>=4;
+        my $products=$in*$in(*1);
+        my $diffs=$products-$products(*1,*1);  # Xi*Xj-Xk*Xl
+        my ($i, $j, $k, $l) = $diffs->ndcoords->mv(0,-1)->dog; #coordinates into ndarray $diffs
+        $diffs=$diffs->where(
+            ($i!=$j)&($i!=$k)&($i!=$l)
+            &($j!=$k)&($j!=$l)
+            &($k!=$l));  # select elements with no repeating coordinates
+        say "$_ -> ", $diffs->max;
     }
     catch($e){
-	warn $e;
+        warn $e;
     }
 }
diff --git a/challenge-339/wlmb/perl/ch-2.pl b/challenge-339/wlmb/perl/ch-2.pl
index 9a81fa78a3..e642cfe3c3 100755
--- a/challenge-339/wlmb/perl/ch-2.pl
+++ b/challenge-339/wlmb/perl/ch-2.pl
@@ -14,9 +14,9 @@ die <<~"FIN" unless @ARGV;
     FIN
 for(@ARGV){
     try{
-	say "$_ -> ", append(0,pdl($_))->cumusumover->max
+        say "$_ -> ", append(0,pdl($_))->cumusumover->max
     }
     catch($e){
-	warn $e;
+        warn $e;
     }
 }
-- 
cgit