From 7cccf2f51d1a1ad5027dcdf2fb9058cd7804808f Mon Sep 17 00:00:00 2001
From: Dave Jacoby <jacoby.david@gmail.com>
Date: Mon, 9 Oct 2023 17:41:11 -0400
Subject: DAJ 238

---
 challenge-238/dave-jacoby/blog.txt     |  1 +
 challenge-238/dave-jacoby/perl/ch-1.pl | 28 ++++++++++++++++++++++
 challenge-238/dave-jacoby/perl/ch-2.pl | 43 ++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 challenge-238/dave-jacoby/blog.txt
 create mode 100644 challenge-238/dave-jacoby/perl/ch-1.pl
 create mode 100644 challenge-238/dave-jacoby/perl/ch-2.pl

diff --git a/challenge-238/dave-jacoby/blog.txt b/challenge-238/dave-jacoby/blog.txt
new file mode 100644
index 0000000000..3c53d53a96
--- /dev/null
+++ b/challenge-238/dave-jacoby/blog.txt
@@ -0,0 +1 @@
+https://jacoby.github.io/2023/10/09/you-cant.html
diff --git a/challenge-238/dave-jacoby/perl/ch-1.pl b/challenge-238/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..fb07484a53
--- /dev/null
+++ b/challenge-238/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,28 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ say postderef signatures state };
+
+my @examples = (
+
+    [ 1, 2,  3, 4, 5 ],
+    [ 1, 1,  1, 1, 1 ],
+    [ 0, -1, 1, 2 ],
+);
+
+for my $e (@examples) {
+    my @output = running_sum( $e->@* );
+    my $input  = join ', ', $e->@*;
+    my $output = join ', ', @output;
+    say <<~"END";
+    Input:  \@int = ($input)
+    Output: ($output)
+    END
+}
+
+sub running_sum (@int) {
+    my $c      = 0;
+    my @output = map { $c += $_; $c } @int;
+    return @output;
+}
diff --git a/challenge-238/dave-jacoby/perl/ch-2.pl b/challenge-238/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..8b47668fa9
--- /dev/null
+++ b/challenge-238/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,43 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ say postderef signatures state };
+
+use Algorithm::Permute;
+use List::Util qw{ product };
+
+my @examples = (
+
+    [ 15, 99, 1,  34 ],
+    [ 50, 25, 33, 22 ],
+);
+
+for my $e (@examples) {
+    my @int    = $e->@*;
+    my $int    = join ', ', @int;
+    my @output = persistence_sort(@int);
+    my $output = join ', ', @output;
+    say <<~"END";
+    Input:  \@int = ($int)
+    Output: ($output)
+    END
+}
+
+sub persistence_sort (@nums) {
+    my @output =
+        map  { $_->[0] }
+        sort { $a->[1] <=> $b->[1] }
+        map  { [ $_, munge($_) ] } sort @nums;
+    return @output;
+}
+
+sub munge ($i) {
+    my $c = 0;
+    while (1) {
+        return $c if $i < 10;
+        $i = product split //, $i;
+        $c++;
+    }
+    return -1; # just in case
+}
-- 
cgit