[perl] p4, p5

1 files changed, 48 insertions, 0 deletions

diff --git a/perl/p5.pl b/perl/p5.pl
new file mode 100755
index 0000000..f63ca34
--- /dev/null
+++ b/perl/p5.pl
@@ -0,0 +1,48 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use List::Util qw(reduce max all);
+
+# Functional
+
+# Imperative
+my @primes = (2);
+sub factorize {
+	my $n = shift;
+	for my $i ($primes[-1] .. $n) {
+		push @primes, $i if all { $i % $_ != 0 } @primes;
+	}
+	my $factors;
+	for my $prime (@primes) {
+		if ($n % $prime == 0) {
+			$factors->{$prime}++;
+			$n /= $prime;
+			redo;
+		}
+	}
+	return $factors;
+}
+
+sub merge_factors {
+	my $fst = shift;
+	my $snd = shift;
+	my $res;
+	foreach my $k (keys %$fst) {
+		$res->{$k} = max($res->{$k} || 0, $fst->{$k});
+	}
+	foreach my $k (keys %$snd) {
+		$res->{$k} = max($res->{$k} || 0, $snd->{$k});
+	}
+	return $res;
+}
+
+my @factors = map { factorize $_ } (2..20);
+my $mcm = reduce { merge_factors($a, $b) } @factors;
+
+my $res = 1;
+foreach my $k (keys %$mcm) {
+	$res *= $k ** $mcm->{$k};
+}
+print $res, "\n";