#!/usr/bin/env perl
#
=head1 Task 2: Max Distance

Submitted by: Mohammad Sajid Anwar

You are given two integer arrays, @arr1 and @arr2.

Write a script to find the maximum difference between any pair of values from
both arrays.

=head2 Example 1

    Input: @arr1 = (4, 5, 7)
           @arr2 = (9, 1, 3, 4)
    Output: 6

    With element $arr1[0] = 4
    | 4 - 9 | = 5
    | 4 - 1 | = 3
    | 4 - 3 | = 1
    | 4 - 4 | = 0
    max distance = 5

    With element $arr1[1] = 5
    | 5 - 9 | = 4
    | 5 - 1 | = 4
    | 5 - 3 | = 2
    | 5 - 4 | = 1
    max distance = 4

    With element $arr1[2] = 7
    | 7 - 9 | = 2
    | 7 - 1 | = 6
    | 7 - 3 | = 4
    | 7 - 4 | = 4
    max distance = 6

    max (5, 6, 6) = 6

=head2 Example 2

    Input: @arr1 = (2, 3, 5, 4)
           @arr2 = (3, 2, 5, 5, 8, 7)
    Output: 6

    With element $arr1[0] = 2
    | 2 - 3 | = 1
    | 2 - 2 | = 0
    | 2 - 5 | = 3
    | 2 - 5 | = 3
    | 2 - 8 | = 6
    | 2 - 7 | = 5
    max distance = 6

    With element $arr1[1] = 3
    | 3 - 3 | = 0
    | 3 - 2 | = 1
    | 3 - 5 | = 2
    | 3 - 5 | = 2
    | 3 - 8 | = 5
    | 3 - 7 | = 4
    max distance = 5

    With element $arr1[2] = 5
    | 5 - 3 | = 2
    | 5 - 2 | = 3
    | 5 - 5 | = 0
    | 5 - 5 | = 0
    | 5 - 8 | = 3
    | 5 - 7 | = 2
    max distance = 3

    With element $arr1[3] = 4
    | 4 - 3 | = 1
    | 4 - 2 | = 2
    | 4 - 5 | = 1
    | 4 - 5 | = 1
    | 4 - 8 | = 4
    | 4 - 7 | = 3
    max distance = 4

    max (5, 6, 3, 4) = 6

=head2 Example 3

    Input: @arr1 = (2, 1, 11, 3)
           @arr2 = (2, 5, 10, 2)
    Output: 9

    With element $arr1[0] = 2
    | 2 - 2  | = 0
    | 2 - 5  | = 3
    | 2 - 10 | = 8
    | 2 - 2  | = 0
    max distance = 8

    With element $arr1[1] = 1
    | 1 - 2  | = 1
    | 1 - 5  | = 4
    | 1 - 10 | = 9
    | 1 - 2  | = 1
    max distance = 9

    With element $arr1[2] = 11
    | 11 - 2  | = 9
    | 11 - 5  | = 6
    | 11 - 10 | = 1
    | 11 - 2  | = 9
    max distance = 9

    With element $arr1[3] = 3
    | 3 - 2  | = 1
    | 3 - 5  | = 2
    | 3 - 10 | = 7
    | 3 - 2  | = 1
    max distance = 7

    max (8, 9, 9, 7) = 9

=head2 Example 4

    Input: @arr1 = (1, 2, 3)
           @arr2 = (3, 2, 1)
    Output: 2

    With element $arr1[0] = 1
    | 1 - 3 | = 2
    | 1 - 2 | = 1
    | 1 - 1 | = 0
    max distance = 2

    With element $arr1[1] = 2
    | 2 - 3 | = 1
    | 2 - 2 | = 0
    | 2 - 1 | = 1
    max distance = 1

    With element $arr1[2] = 3
    | 3 - 3 | = 0
    | 3 - 2 | = 1
    | 3 - 1 | = 2
    max distance = 2

    max (2, 1, 2) = 2

=head2 Example 5

    Input: @arr1 = (1, 0, 2, 3)
           @arr2 = (5, 0)
    Output: 5

    With element $arr1[0] = 1
    | 1 - 5 | = 4
    | 1 - 0 | = 1
    max distance = 4

    With element $arr1[1] = 0
    | 0 - 5 | = 5
    | 0 - 0 | = 0
    max distance = 5

    With element $arr1[2] = 2
    | 2 - 5 | = 3
    | 2 - 0 | = 2
    max distance = 3

    With element $arr1[3] = 3
    | 3 - 5 | = 2
    | 3 - 0 | = 3
    max distance = 3

    max (4, 5, 3, 3) = 5

=cut

use strict;
use warnings;
use Test2::V0 -no_srand => 1;
use Data::Dumper;

my $cases = [
    [[[4, 5, 7],     [9, 1, 3, 4]],       6, "Example 1"],
    [[[2, 3, 5, 4],  [3, 2, 5, 5, 8, 7]], 6, "Example 2"],
    [[[2, 1, 11, 3], [2, 5, 10, 2]],      9, "Example 3"],
    [[[1, 2, 3],     [3, 2, 1]],          2, "Example 4"],
    [[[1, 0, 2, 3],  [5, 0]],             5, "Example 5"],
];

sub max_distance
{
    my $arr1 = $_[0]->[0];
    my $arr2 = $_[0]->[1];

    my $max = 0;
    for my $i (0 .. $#$arr1) {
        for my $j (0 .. $#$arr2) {
            my $dist = abs($arr1->[$i] - $arr2->[$j]);
            $max = $dist if $dist > $max;
        }
    }
    return $max;
}

for (@$cases) {
    is(max_distance($_->[0]), $_->[1], $_->[2]);
}
done_testing();

exit 0;