<?PHP

$sort = array(
    0 => 50,1 => 100,2 => 150
);

$default = $sort;
sort($sort);

$flag = true;
foreach($sort as $key=>$value)
    if($value!=$default[$key])
        $flag = false;  

if($flag)
    echo "Already sorted";  
else
    echo "Not Already sorted";  
?>