Challenge 123 Task1 LK Perl

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+#!/usr/bin/perl 
+#===============================================================================
+#
+#         FILE: ch-1.pl
+#
+#        USAGE: ./ch-1.pl  
+#
+#  DESCRIPTION: The Weekly Challenge #123
+#               Task 1 - Ugly Numbers
+#  
+#       AUTHOR: Lubos Kolouch
+#      CREATED: 07/30/2021 01:24:00 PM
+#===============================================================================
+
+use strict;
+use warnings;
+use List::Util qw/min/;
+use Data::Dumper;
+
+
+# So, I spent a lot of time on this... the reason is that I got sidetracked by
+# the sentence "Ugly numbers are those number whose prime factors are 2, 3 or
+# 5".
+#
+# So means that if I take number 14, it fits into this as 14 = 2 * 7, meaning
+# that prime factor 2 meets the condition "2, 3 or 5".
+#
+# It even passed the tests suggested in the excercise as the biggest number
+# returned (12) is below 14.
+#
+# Then I added more tests and realized, that the sentence should read something
+# like "...whose prime factors are 2, 3 or 5 ONLY".
+#
+# Anyway, finally I just implemented the alghoritm from
+# https://www.geeksforgeeks.org/ugly-numbers/
+
+sub get_n_ugly {
+    my $what = shift;
+
+    my @ugly_cache = [1];
+
+    my $ugly_2 = 2;
+    my $index_2 = 0;
+    my $ugly_3 = 3;
+    my $index_3 = 0;
+    my $ugly_5 = 5;
+    my $index_5 = 0;
+
+    for my $pos (1..$what-1) {
+        my $next_ugly = min($ugly_2, $ugly_3, $ugly_5);
+        $ugly_cache[$pos] = $next_ugly;
+
+        if ($next_ugly == $ugly_2) {
+            $index_2++;
+            $ugly_2 = $ugly_cache[$index_2] * 2;
+        }
+
+        if ($next_ugly == $ugly_3) {
+            $index_3++;
+            $ugly_3 = $ugly_cache[$index_3] * 3;
+        }
+
+        if ($next_ugly == $ugly_5) {
+            $index_5++;
+            $ugly_5 = $ugly_cache[$index_5] * 5;
+        }
+
+    }
+
+    return $ugly_cache[-1];
+}
+
+
+use Test::More;
+
+is(get_n_ugly(7), 8);
+is(get_n_ugly(10), 12);
+is(get_n_ugly(150), 5832);
+done_testing;
+