Solves the denominations problems.

Denominatios Problem

$denominations = array(0.5, 1, 2); 
$total = 3.6; 


for ($i = $total; $i > 0; $i = $i - $denominations[count($denominations)-1]) {
    while ( $i < end($denominations) ){ 
        unset($denominations[count($denominations)-1]);
    }
    if (empty($denominations)){ 
        break; 
    } 
    $results[] = $denominations[count($denominations)-1];
}

if ($i > 0){ 
    $results[] = $i;
} 

/* 
 Returns: 
 Array
(
    [0] => 2
    [1] => 1
    [2] => 0.5
    [3] => 0.1
)
*/