Solution to task 2

1 files changed, 65 insertions, 0 deletions

diff --git a/challenge-244/jo-37/perl/ch-2.pl b/challenge-244/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..4a51d8fba7
--- /dev/null
+++ b/challenge-244/jo-37/perl/ch-2.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use bigint;
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [N...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N...
+    list of numbers
+
+EOS
+
+
+### Input and Output
+
+say total_power(@ARGV);
+
+
+### Implementation
+
+sub total_power {
+    my @s = sort {$a <=> $b} @_;
+    my $power;
+    while (defined (my $min = $s[0])) {
+        while (my ($offs, $max) = each @s) {
+            $power += $min * $max**2 * ($offs ? 2**($offs - 1) : 1);
+        }
+    } continue {
+        shift @s;
+    }
+
+    $power;
+}
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is total_power(2, 1, 4), 141, 'example 1';
+    }
+
+    SKIP: {
+
+        is total_power(2, 3, 5, 7), 1627, 'example from blog';
+        is total_power((2) x 64), (2**64 - 1) * 2 * 2**2,
+            '147573952589676412920';
+	}
+
+    done_testing;
+    exit;
+}