Solution to task 1

1 files changed, 22 insertions, 0 deletions

diff --git a/challenge-078/jo-37/perl/ch-1.pl b/challenge-078/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..34a1cbdd96
--- /dev/null
+++ b/challenge-078/jo-37/perl/ch-1.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/perl
+
+use Test2::V0;
+use List::Util 'reduce';
+
+# Viewing at the array from right to left.  Every element that is larger
+# than the current first leading element is leading too and is prepended
+# to the list.  Appending (0) to an empty list as requested, though this
+# leads to ambiguous results.
+sub leading {
+	(@{(reduce {
+		unshift @$a, $b if $b > ($a->[0] // '-inf');
+		$a;
+	} [], reverse @_)}, (0) x !@_) ;
+}
+
+is [leading 9, 10, 7, 5, 6, 1], [10, 7, 6, 1], 'first example'; 
+is [leading 3, 4, 5], [5], 'second example';
+is [leading], [0], 'no leader';
+is [leading -1, 0], [0], 'ambiguous result';
+
+done_testing;