PHP算法：冒泡排序与快速排序

写一个排序算法，可以是冒泡排序或者快速排序，假设待排序对象是一个二维数组。（提示：不能使用系统已有函数，另外请仔细回忆以前学习过的基础知识）

//冒泡排序<br>
function bubble_sort($array)
{
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	$count = count($array);
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	if ($count <= 0) return false;

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	for($i=0; $i<$count; $i++){
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		for($j=$count-1; $j>$i; $j--){
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			if ($array[$j] < $array[$j-1]){
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				$tmp = $array[$j];
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				$array[$j] = $array[$j-1];
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				$array[$j-1] = $tmp;
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			}
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		}
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	}
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	return $array;
<br>
}