problem11.pl

#!/bin/perl -Tw

use Data::Dumper;
use List::Util qw(max);

my $string_data = "08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48";
my @data = split / /, $string_data;
my @matrix;
for my $row (0..19) {
    for my $column (0..19) {
        $value = shift @data;
        $matrix[$row][$column] = int($value);
    }
}

my $max_product = 0;
for my $row (0..19) {
    for my $column (0..19) {
        $p1 = product_up($column, $row);
        $p2 = product_down($column, $row);
        $p3 = product_left($column, $row);
        $p4 = product_right($column, $row);
        $p5 = product_up_left($column, $row);
        $p6 = product_up_right($column, $row);
        $p7 = product_down_left($column, $row);
        $p8 = product_down_right($column, $row);
        print "$p1 $p2 $p3 $p4 $p5 $p6 $p7 $p8\n";
        @nums = ($p1, $p2, $p3, $p4, $p5, $p6, $p7, $p8, $max_product);
        $max_product = max(@nums);
        print "Maxmimum so far: $max_product\n";
    }
}

sub product_up {
    my ($x, $y) = @_;

    if ($y-3 < 0) {
        return 0;
    }
    $product = 1;
    for my $cy (0..3) {
        $product = $product * $matrix[$y - $cy][$x];
    }
    return $product;
}

sub product_down {
    my ($x, $y) = @_;

    if ($y+3 > 19) {
        return 0;
    }
    $product = 1;
    for my $cy (0..3) {
        $product = $product * $matrix[$y + $cy][$x];
    }
    return $product;
}

sub product_right {
    my ($x, $y) = @_;

    if ($x+3 > 19) {
        return 0;
    }
    $product = 1;
    for my $cx (0..3) {
        $product = $product * $matrix[$y][$x + $cx];
    }
    return $product;
}

sub product_left {
    my ($x, $y) = @_;

    if ($x-3 < 0) {
        return 0;
    }
    $product = 1;
    for my $cx (0..3) {
        $product = $product * $matrix[$y][$x - $cx];
    }
    return $product;
}

sub product_up_left {
    my ($x, $y) = @_;

    if ($x-3 < 0) {
        return 0;
    }
    if ($y-3 < 0) {
        return 0;
    }
    $product = 1;
    for my $dx (0..3) {
        $product = $product * $matrix[$y - $dx][$x - $dx];
    }
    return $product;
}

sub product_up_right {
    my ($x, $y) = @_;

    if ($x+3 > 19) {
        return 0;
    }
    if ($y-3 < 0) {
        return 0;
    }
    $product = 1;
    for my $dx (0..3) {
        $product = $product * $matrix[$y - $dx][$x + $dx];
    }
    return $product;
}

sub product_down_left {
    my ($x, $y) = @_;

    if ($x-3 < 0) {
        return 0;
    }
    if ($y+3 > 19) {
        return 0;
    }
    $product = 1;
    for my $dx (0..3) {
        $product = $product * $matrix[$y + $dx][$x - $dx];
    }
    return $product;
}

sub product_down_right {
    my ($x, $y) = @_;

    if ($x+3 > 19) {
        return 0;
    }
    if ($y+3 > 19) {
        return 0;
    }
    $product = 1;
    for my $dx (0..3) {
        $product = $product * $matrix[$y + $dx][$x + $dx];
    }
    return $product;
}