#!/usr/bin/env perl

use strict;
use warnings;

use List::Util qw{min max};

# Built-in functions

my @values = (7,9,2,0,1,2,4,3,9);
print 'Min:   ', min(@values), "\n";
print 'Max:   ', max(@values), "\n";
print 'Count: ', 0+@values, "\n";

# How to get from (0,0) at top left to bottom left

my @matrix = (
    [' ' x 2, '*', ' ' x 2],
    [' ', '*', ' ', '*', ' '],
    ['*', ' ' x 3, '*'],
);

print "\nOriginal:\n";

for (0 .. $#matrix) {
    print @{$matrix[$_]}, "\n";
}

print "\nInverted:\n";

for (reverse 0 .. $#matrix) {
    print @{$matrix[$_]}, "\n";
}

# A complete guess about your graph

my @graph;

for (0 .. max(@values)) {
    $graph[$_] = [(' ') x @values];
}

for my $i (0 .. $#values) {
    $graph[$values[$i]][$i] = '*';
}

print "\nGraph:\n";

for (reverse 0 .. $#graph) {
    print @{$graph[$_]}, "\n";
}