https://theweeklychallenge.org/blog/perl-weekly-challenge-306/

2 files changed, 35 insertions, 0 deletions

diff --git a/challenge-306/kjetillll/perl/ch-1.pl b/challenge-306/kjetillll/perl/ch-1.pl
new file mode 100644
index 0000000000..397d5f41fb
--- /dev/null
+++ b/challenge-306/kjetillll/perl/ch-1.pl
@@ -0,0 +1,17 @@
+#https://theweeklychallenge.org/blog/perl-weekly-challenge-306/
+
+sub sos {  #sum odd subarrays
+    eval join '+', #sum
+    map {
+        my $len = $_;
+        map @_[ $_ .. $_+$len-1 ], 0 .. @_ - $len  #elems in all subarrays of length $len
+    }
+    grep $_ % 2, #only odd lengths
+    1 .. @_;     #sub array lengths
+}
+
+use Test::More tests => 2;
+is sos( @{ $$_{input} } ), $$_{output} for
+{input => [2,5,3,6,4], output => 77},
+{input => [1,3],       output => 4}
+    
diff --git a/challenge-306/kjetillll/perl/ch-2.pl b/challenge-306/kjetillll/perl/ch-2.pl
new file mode 100644
index 0000000000..96b046215f
--- /dev/null
+++ b/challenge-306/kjetillll/perl/ch-2.pl
@@ -0,0 +1,18 @@
+#https://theweeklychallenge.org/blog/perl-weekly-challenge-306/
+
+sub last_elem {
+    my($y, $x, @rest) = sort { $b <=> $a } @_;
+    ! @_    ? 0
+    : @_==1 ? @_
+    :         last_elem( @rest, $x == $y ? () : $y - $x )
+}
+
+use Test::More tests => 2;
+is last_elem(@{ $$_{input} }), $$_{output} for
+{ input => [3, 8, 5, 2, 9, 2], output => 1 },
+{ input => [3, 2, 5],          output => 0 },
+
+__END__
+Todo: speedup / algorithm improvement for large lists:
+sort list only once and use List::BinarySearch::XS::binsearch_pos() to
+find the insert positions for y-x when y != x, insert with splice()