Merge pull request #43 from dmanto/daniel-mantovani-challenge3-branch

for ch-003 ch-1.pl

1 files changed, 38 insertions, 0 deletions

diff --git a/challenge-003/daniel-mantovani/perl5/ch1-pl b/challenge-003/daniel-mantovani/perl5/ch1-pl
new file mode 100644
index 0000000000..fa23ce0075
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+++ b/challenge-003/daniel-mantovani/perl5/ch1-pl
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+#!/usr/bin/perl
+use strict;
+use warnings;
+use v5.10;
+
+my $q = $ARGV[0];
+
+die
+  "Usage: perl $0 <n>\n\nwhere <n> is the (integer) quantity of hamming numbers you ask"
+  unless $q && $q =~ /^\d+$/;
+
+my @primes = (2, 3, 5);
+
+# for each prime, we will define one vector (array), whith just one element [1]
+# note that [1] will be first hamming code inside each array!
+
+my %vec;
+$vec{$_} = [1] for @primes;
+
+for my $i (1 .. $q) {
+
+# just look for the min value from the head of v2, v3 or v5
+# (without using List::Util, as the challenge encourages no to use external modules)
+  my $h;
+  map { $h = $vec{$_}[0] unless $h && $h < $vec{$_}[0] } @primes;
+
+  # and we just got the next hamming number!
+  say "$i\t", $h;
+
+  for my $f (@primes) {    # now for every prime factor
+        # remove this value on each vector where it is present
+    shift @{$vec{$f}} if $vec{$f}[0] == $h;
+
+    # and finally calculate and insert new values to each vector
+    # note that new pushed value is higer than any previous value in each vector
+    push @{$vec{$f}}, $h * $f;
+  }
+}