半素数を列挙する

lang/perl/semiprime/math_big_factors.pl

@@ -0,0 +1,10 @@
+#!/opt/local/bin/perl
+use strict;
+use warnings;
+
+use Math::Big::Factors qw(factors_wheel);
+
+for my $num (1..99) {
+    my @factors = factors_wheel($num);
+    print "$num\n" if scalar(@factors) == 2;
+}

lang/perl/semiprime/no_module.pl

@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+# 最小の素因数を返すサブルーチン
+# 引数が素数だった場合はundefを返す
+sub get_factor {
+    my $target = shift;
+    for my $num (2 .. $target-1) {
+        if ($target % $num == 0) {
+            return $num;
+        }
+    }
+    return;
+}
+
+TARGET: for my $num (1..99) {
+    my $first_factor = get_factor($num);
+    if (!defined($first_factor)) {
+        next TARGET;
+    }
+
+    my $second_factor = get_factor($num / $first_factor);
+    if (!defined($second_factor)) {
+        print "$num\n";
+    }
+}