array("id" => 2, "name" => "Take That", "rating" => 1),

array("id" => 3, "name" => "The Killers", "rating" => 4),
array("id" => 4, "name" => "Lusain", "rating" => 3)

); 
foreach ($data as $key => $value) {

$name[$key] = $value['name'];
$rating[$key] = $value['rating'];

}
array_multisort($rating, $name, $data); 

print_r($data);
?>

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8.---------------------------- 

 

数据库中有两个字段 id, sorce.假设 sorce

 

的取值范围是 5-10.

按照以下概率实现 sorce 数据的更新。

5(25%) => 6 5(25%) => 7
6(20%) => 7 

7(25%) => 8 7(25%) => 6
8(10%) => 6 8(25%) => 9

9(15%) => 8 9(20%) => 10
10(25%) => 9

要求考虑性能及扩展性。写出概率分布相关代码。
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9.----------------------------

设计一个缓存系统。写出思路。画出图。考虑命中，生存期等多种要素。
答：可以参考 memcached

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