合并两个有序数组

<?php /*
$data1 数组A
$data2 数组B
$num1  数组A的有效元素个数
*/
function merge(&$data1,$data2,$num1)
{
	$total=count($data1);
	$num2=count($data2);
	while($num1>0&&$num2>0)
	{
		if($data1[$num1-1]>$data2[$num2-1])
		{
			$data1[$total-1]=$data1[$num1-1];
			$total--;
			$num1--;
		}
		else
		{
			$data1[$total-1]=$data2[$num2-1];
			$total--;
			$num2--;
		}
	}
	if($num2>0)
	{
		while($total>0&&$num2>0)
		{
			$data1[$total-1]=$data2[$num2-1];
			$total--;
			$num2--;
		}
	}
}

$a=array(1,3,5,7,9,0,0,0,0,0);
$b=array(2,4,6,8,10);
merge($a,$b,5);
print_r($a);