Add implementation for challenge 140 task 02

1 files changed, 80 insertions, 0 deletions

diff --git a/challenge-140/alexander-pankoff/perl/ch-2.pl b/challenge-140/alexander-pankoff/perl/ch-2.pl
new file mode 100644
index 0000000000..b0cb877ed5
--- /dev/null
+++ b/challenge-140/alexander-pankoff/perl/ch-2.pl
@@ -0,0 +1,80 @@
+use strict;
+use warnings;
+use feature qw'say signatures';
+no warnings 'experimental::signatures';
+
+use constant DEBUG => $ENV{DEBUG} // 0;
+
+run() unless caller();
+
+sub run() {
+    my $i = prompt_for_integer('i');
+    my $j = prompt_for_integer('j');
+    my $k = prompt_for_integer('k');
+
+    my $matrix        = multiplication_matrix( $i, $j );
+    my @sorted_matrix = sort_multiplication_matrix($matrix);
+    my $res           = $sorted_matrix[ $k - 1 ];
+
+    if (DEBUG) {
+        say "Since the multiplication of $i x $j is as below:";
+
+        say render_matrix($matrix);
+        say "The sorted multiplication table:";
+        say join( ' ', @sorted_matrix );
+
+        say "Now the " . to_ordinal($k) . " element in the table is '$res'";
+
+    }
+
+    say $res;
+
+}
+
+sub multiplication_matrix ( $i, $j ) {
+    [
+        map {
+            my $row = $_;
+            [
+                map {
+                    my $col = $_;
+                    $col * $row;
+
+                } ( 1 .. $j )
+            ];
+        } ( 1 .. $i )
+    ];
+}
+
+sub sort_multiplication_matrix($matrix) {
+    sort { $a <=> $b } map { @$_ } @$matrix;
+}
+
+sub render_matrix($matrix) {
+    my $max        = $matrix->[-1][-1];
+    my $width      = length $max;
+    my $format_str = "%$width" . 'd';
+
+    join(
+        "\n",
+        map {
+            join( " ", map { sprintf( $format_str, $_ ) } @$_ )
+        } @$matrix
+    );
+}
+
+sub to_ordinal($n) {
+    return ( $n == 1 ) ? "1st" : $n == 2 ? "2nd" : $n == 3 ? "3rd" : $n . 'th';
+}
+
+sub prompt_for_integer($name) {
+    say "Enter integer number $name greater or equal to 1.";
+    chomp( my $number = <STDIN> );
+
+    if ( $number !~ m/^\d+$/ || $number < 1 ) {
+        say "Invalid integer.";
+        return prompt_for_integer($name);
+    }
+
+    return $number;
+}