Solution to task 2

1 files changed, 60 insertions, 0 deletions

diff --git a/challenge-258/jo-37/perl/ch-2.pl b/challenge-258/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..c9bf4e62d7
--- /dev/null
+++ b/challenge-258/jo-37/perl/ch-2.pl
@@ -0,0 +1,60 @@
+#!/usr/bin/perl -s
+
+use v5.24;
+use Test2::V0;
+use List::Util 'sum0';
+
+our ($tests, $examples, $bits);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless defined $bits and @ARGV;
+usage: $0 [-examples] [-tests] [-bits=K] [N...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-bits=K
+    sum over numbers with a k-bit index
+
+N...
+    list of numbers
+
+EOS
+
+
+### Input and Output
+
+say k_bit_sum($bits, @ARGV);
+
+
+### Implementation
+
+sub k_bit_sum {
+	my $k = shift;
+
+    sum0 @_[grep unpack('%32b*', pack('l', $_)) == $k, 0 .. $#_];
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is k_bit_sum(1 ,=> 2, 5, 9, 11, 3), 17, 'example 1';
+        is k_bit_sum(2 ,=> 2, 5, 9, 11, 3), 11, 'example 2';
+        is k_bit_sum(0 ,=> 2, 5, 9, 11, 3), 2, 'example 3';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}