PHP标准库 (SPL)实现常用数据结构

php标准库(spl)

栈:先进后出，后进先出

$q = new SplStack();

$q[] = 1;

$q[] = 2;

$q[] = 3;

$q->push(4);

$q->add(4,5);

$q->rewind();

while(

$q->valid()){

echo

$q->current(),"\n";

$q->next();

}

?>

Output

5

4

3

2

1

队列:先进先出，后进后出

$queue = new SplQueue();

$queue->enqueue('A');

$queue->enqueue('B');

$queue->enqueue('C');

$queue->rewind();

while(

$queue->valid()){

echo

$queue->current(),"\n";

$queue->next();

}

print_r($queue);

$queue->dequeue(); //remove first one

print_r($queue);

?>

Output

A

B

C

SplQueue Object

(

[flags:SplDoublyLinkedList:private] => 4

[dllist:SplDoublyLinkedList:private] => Array

(

[0] => A

[1] => B

[2] => C

)

)

SplQueue Object

(

[flags:SplDoublyLinkedList:private] => 4

[dllist:SplDoublyLinkedList:private] => Array

(

[0] => B

[1] => C

)

)

小顶堆: 堆的每个父节点都小于孩子节点

$h = new SplMinHeap();

// [parent, child]

$h->insert([9, 11]);

$h->insert([0, 1]);

$h->insert([1, 2]);

$h->insert([1, 3]);

$h->insert([1, 4]);

$h->insert([1, 5]);

$h->insert([3, 6]);

$h->insert([2, 7]);

$h->insert([3, 8]);

$h->insert([5, 9]);

$h->insert([9, 10]);

for (

$h->top(); $h->valid(); $h->next()) {

list(

$parentId, $myId) = $h->current();

echo

"$myId ($parentId)\n";

}

固定长度数组:

$array = new SplFixedArray(5);

$array[1] = 2;

$array[4] = "foo";

var_dump($array[0]); // NULL

var_dump($array[1]); // int(2)

var_dump($array["4"]); // string(3) "foo"