Solution to task 2

1 files changed, 28 insertions, 0 deletions

diff --git a/challenge-090/jo-37/perl/ch-2.pl b/challenge-090/jo-37/perl/ch-2.pl
new file mode 100755
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+++ b/challenge-090/jo-37/perl/ch-2.pl
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+#!/usr/bin/perl
+
+use integer;
+use Test2::V0;
+
+# Implement Ethiopian multiplication
+sub ethiopian_mult {
+	my ($p, $q) = splice @_, 0, 2;
+	# The method is more effective if the first number is the smaller
+	# one.
+	($p, $q) = ($q, $p) if $p > $q;
+
+	my $prod = 0;
+	while ($p) {
+		# Add second number if the first is odd
+		$prod += ($p % 2) * $q;
+		# Get next pair.
+		($p, $q) = ($p / 2, $q * 2);
+	}
+
+	$prod;
+}
+
+is ethiopian_mult(14, 12), 168, 'Example 1';
+is ethiopian_mult(2**32, 0), 0, 'Multiply by zero';
+is ethiopian_mult(2**32, 1), 2**32, 'Multiply by one';
+
+done_testing;