Add solutions for week 285

Also add a blog link.

3 files changed, 59 insertions, 0 deletions

diff --git a/challenge-285/torgny-lyon/blog.txt b/challenge-285/torgny-lyon/blog.txt
new file mode 100644
index 0000000000..8bcedb064c
--- /dev/null
+++ b/challenge-285/torgny-lyon/blog.txt
@@ -0,0 +1 @@
+https://www.abc.se/~torgny/pwc.html#285
diff --git a/challenge-285/torgny-lyon/perl/ch-1.pl b/challenge-285/torgny-lyon/perl/ch-1.pl
new file mode 100755
index 0000000000..411ec12964
--- /dev/null
+++ b/challenge-285/torgny-lyon/perl/ch-1.pl
@@ -0,0 +1,14 @@
+#!/usr/bin/perl
+
+use v5.40;
+
+use Test::More tests => 2;
+
+sub get_no_connection {
+    my ($c) = my %r = map { $_->[0], $_->[1] } @_;
+    $c = $r{$c} while $r{$c};
+    return $c;
+}
+
+is(get_no_connection([ 'B', 'C' ], [ 'D', 'B' ], [ 'C', 'A' ]), 'A');
+is(get_no_connection([ 'A', 'Z' ]), 'Z');
diff --git a/challenge-285/torgny-lyon/perl/ch-2.pl b/challenge-285/torgny-lyon/perl/ch-2.pl
new file mode 100755
index 0000000000..908ec5172a
--- /dev/null
+++ b/challenge-285/torgny-lyon/perl/ch-2.pl
@@ -0,0 +1,44 @@
+#!/usr/bin/perl
+
+use v5.40;
+
+use List::Util qw(first);
+use Test::More tests => 3;
+
+my %coins = (
+    50 => [ [ 25, 25 ], [ 10, 10, 10, 10, 10 ] ],
+    25 => [ [ 10, 10, 5 ] ],
+    10 => [ [ 5, 5 ] ],
+    5  => [ [ 1, 1, 1, 1, 1 ] ],
+    1  => [ [1] ],
+);
+
+sub make_change {
+    my $n = shift;
+    my @l;
+    while ($n > 0) {
+        my $coin = first { $_ <= $n } sort { $b <=> $a } keys %coins;
+        push @l, $coin;
+        $n -= $coin;
+    }
+    return f([@l], {});
+}
+
+sub f {
+    my @l = sort @{ $_[0] };
+    my $h = $_[1];
+    return if exists $h->{"@l"};
+    $h->{"@l"} = 1;
+    foreach my $i (grep { $l[$_] != 1 } 0..$#l) {
+        foreach (@{ $coins{ $l[$i] } } ) {
+            my @a = @l;
+            splice @a, $i, 1, @{$_};
+            f([@a], $h);
+        }
+    }
+    return keys %$h;
+}
+
+is(make_change(9), 2);
+is(make_change(15), 6);
+is(make_change(100), 292);