Question

i have a 1D arrayA and a 2D arrayB.

arrayA[0] = 'D'
arrayA[1] = 'U'
arrayA[3] = 'R'
arrayA[4] = 'B'
arrayA[5] = 'S'
arrayA[6] = 'H'

arrayB[0][0] = 'D'   arrayB[0][1] = 2   
arrayB[1][0] = 'B'   arrayB[1][1] = 1
arrayB[2][0] = 'R'   arrayB[2][1] = 1
arrayB[3][0] = 'U'   arrayB[3][1] = 1
arrayB[4][0] = 'H'   arrayB[4][1] = 0
arrayB[5][0] = 'S'   arrayB[5][1] = 0

arrayB[x][y] is sorted – based on y.

I have to create a new array using the letters, first giving priority on y from arrayB[x][y].
But there are some same values in y like, 1 three times and 0 two times.
In this situation similar values will be sorted according to arrayA.

and the new array will sort like :

D, U, R, B, S, H

How can i do it efficiently ?

thanks in advance

Answer 1

In the code below, $string corresponds to arrayB[x][0], $weight corresponds to arrayB[x][1] and $order corresponds to arrayA:

<?php

$string = str_split('DBRUHS');
$weight = str_split('211100');
$result = '';

function my_sort($a, $b)
{
    $order = str_split('DURBSH');
    $a = array_search($a, $order);
    $b = array_search($b, $order);
    if ($a === $b) return 0;
    if ($a === FALSE) return -1;
    if ($b === FALSE) return 1;
    if ($a == $b) return 0;
    return ($a < $b) ? -1 : 1;
}

arsort($weight);
$current_priority = -1;
$substring = array();
$max = count($weight);
$count = 1;
foreach ($weight as $position => $priority)
{
    if ($count++ == $max)
    {
        $substring[] .= $string[$position];
        $priority = $current_priority + 1;
    }
    if ($current_priority != $priority)
    {
        if (!empty($substring))
        {
            usort($substring, 'my_sort');
            $result .= implode('', $substring);
        }
        $current_priority = $priority;
        $substring = array($string[$position]);
    }
    else
    {
        $substring[] = $string[$position];
    }
}

print_r(str_split($result));

?>