Question

I try to write a script and a problem. Can you let me know if you know how i can do this or ask someone if they know how can this be possibe.

1. Max numbers which can be selected 1 to 20 numbers. it can loop and select any number between 1-20
2. ignore these numbers e.g. 1,2,4,6,9,12 this will be array which can change.
3. each array line can have upto 4 numbers
4. Each array line needs to be unique
   5.I need to have around 10 arrays unique
5. Max 2 numbers can match previous numbers see below.

How can i go about doing this. Any help would be great.

e.g.


Array(
    [0] => Array
    (
        [0] => 3
        [1] => 16
        [2] => 22
        [3] => 24
    )
    [1] => Array
    (
        [0] => 3
        [1] => 16
        [2] => 7
        [3] => 13
    )
    [2] => Array
    (
        [0] => 20
        [1] => 17
        [2] => 10
        [3] => 18
    )
)


This not allow as some array match each other



Array(
    [0] => Array
    (
        [0] => 3
        [1] => 16
        [2] => 22
        [3] => 24
    )
    [1] => Array - cant have this as 3 of the numbers matchs the previous array.only two numbers can match.
    (
        [0] => 3
        [1] => 16
        [2] => 22
        [3] => 13
    )
    [2] => Array
    (
        [0] => 20
        [1] => 17
        [2] => 10
        [3] => 18
    )
)

Thank you.

Answer 1

This seems to satisfy your conditions: http://codepad.viper-7.com/WHkQeD

<?php
$num_arrays = 10; $num_elements = 4;
$min = 1; $max = 20;
$exclude_numbers = array( 1, 4, 6); // Add numbers here to exclude

$answer = array();
for( $i = 0; $i < $num_arrays; $i++)
{
    $answer[$i] = array();
    for( $j = 0; $j < $num_elements; $j++)
    {
        do
        {
            $current = rand( $min, $max);
            // If the previous array exists and there are more than two common elements when we add the $current element, continue
            if( isset( $answer[$i-1]) && count( array_intersect( $answer[$i-1], array_merge( $answer[$i], array( $current))) > 2)
            {
                continue;
            }
        } while( in_array( $current, $exclude_numbers) || in_array( $current, $answer[$i]));
        $answer[$i][$j] = $current;
    }
}

var_dump( $answer);

Edit: Here is a complete solution that satisfies all of your criteria.

Demo

<?php
$num_arrays = 10; $num_elements = 4;
$min = 1; $max = 20;
$exclude_numbers = array( 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);

$answer = array();
for( $i = 0; $i < $num_arrays; $i++)
{
    $answer[$i] = array();
    for( $j = 0; $j < $num_elements; $j++)
    {
        do
        {
            // Get a random element
            $current = rand( $min, $max);
            $new_array = array_merge( $answer[$i], array( $current));

            // If the previous array has more than two common elements (because of the added $current), get a new $current
            if( isset( $answer[$i-1]) && count( array_intersect( $answer[$i-1], $new_array)) > 2)
            {
                $answer[$i] = array_diff( $new_array, $answer[$i-1]);
                $j = count( $answer[$i]) - 1;
                continue;
            }
        } while( in_array( $current, $exclude_numbers) || in_array( $current, $answer[$i]));

        $answer[$i][$j] = $current; 

        // If the array is complete, we need to check for unique arrays
        if( count( $answer[$i]) == $num_elements)
        {
            $k = $i - 1;
            while( $k >= 0)
            {
                if( count( array_diff( $answer[$k],  $answer[$i])) == 0)
                {
                    // This array is the same as a previous one, start over
                    $answer[$i] = array();
                    $j = -1;
                    break;
                }
                $k--;
            }
            // Optionally sort each array
            sort( $answer[$i]);
        }
    }
}

var_dump( $answer);