[023#2]

1 files changed, 33 insertions, 0 deletions

diff --git a/023/ch2.pl b/023/ch2.pl
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+++ b/023/ch2.pl
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+#!/usr/bin/env perl
+#
+# Create a script that prints Prime Decomposition of a given number. The prime
+# decomposition of a number is defined as a list of prime numbers which when all
+# multiplied together, are equal to that number. For example, the Prime
+# decomposition of 228 is 2,2,3,19 as 228 = 2 * 2 * 3 * 19.
+################################################################################
+
+use strict;
+use warnings;
+
+use List::Util qw<any>;
+
+my $n = my $number = shift or die "Usage: $0 <number>";
+
+my @primes = (2);
+my @factors;
+while ($n != 1) {
+    my $lastp = $primes[-1];
+    if ($n % $lastp == 0) {
+        push @factors, $lastp;
+        $n /= $lastp;
+    } else {
+        $lastp++ while any { $lastp % $_ == 0 } @primes;
+        push @primes, $lastp;
+    }
+}
+
+print "$number = ", join("*", @factors), "\n";
+
+# Quick test
+$n *= $_ foreach (@factors);
+$n == $number or die "Oops, something went wrong!";