你能帮我将这个C++代码重写为PHP语言的吗?
/*
B+树是一种常用的多路搜索树,常被用于数据库索引系统中。B+树的特点是能够保持数据稳定有序,并且通过链表相连的叶子节点便于区间查找。
*/
//定义B+树节点结构体
struct BplusTreeNode {
int key[N];
int child[N+1];
int total;
bool is_leaf;
};
//定义B+树类
class BplusTree {
public:
BplusTree() {
root = NULL;
}
//查询key是否在B+树中
bool search(int key) {
if (root == NULL)
return false;
else {
int index = search_index(key, root);
if (index == root->total)
return false;
else if (key == root->key[index])
return true;
else if (root->is_leaf)
return false;
else
return search(key, root->child[index]);
}
}
//插入key到B+树中
void insert(int key) {
if (root == NULL)
root = new BplusTreeNode();
if (root->total == 2*N-1) {
BplusTreeNode *new_root = new BplusTreeNode();
new_root->is_leaf = false;
new_root->child[0] = root;
root = new_root;
split_child(root, 0);
}
insert_nonfull(key, root);
}
private:
BplusTreeNode *root;
//查找key的插入位置
int search_index(int key, BplusTreeNode *node) {
int low = 0, high = node->total-1;
while (low <= high) {
int mid = (low+high) / 2;
if (node->key[mid] == key)
return mid;
else if (node->key[mid] > key)
high = mid-1;
else
low = mid+1;
}
return low;
}
//递归查找key是否在B+树中
bool search(int key, BplusTreeNode *node) {
int index = search_index(key, node);
if (index == node->total || key < node->key[index])
return false;
else if (key == node->key[index])
return true;
else if (node->is_leaf)
return false;
else
return search(key, node->child[index]);
}
//将节点node中的child[index]子树分裂成两个子树
void split_child(BplusTreeNode *node, int index) {
BplusTreeNode *child_node = node->child[index];
BplusTreeNode *new_node = new BplusTreeNode();
new_node->is_leaf = child_node->is_leaf;
new_node->total = N-1;
for (int i = 0; i < N-1; i++)
new_node->key[i] = child_node->key[i+N];
if (!child_node->is_leaf) {
for (int i = 0; i < N; i++)
new_node->child[i] = child_node->child[i+N];
}
child_node->total = N-1;
for (int i = node->total; i >= index+1; i--)
node->child[i+1] = node->child[i];
node->child[index+1] = new_node;
for (int i = node->total-1; i >= index; i--)
node->key[i+1] = node->key[i];
node->key[index] = child_node->key[N-1];
node->total++;
}
//将key插入非满节点node中
void insert_nonfull(int key, BplusTreeNode *node) {
int index = search_index(key, node);
if (node->is_leaf) {
for (int i = node->total-1; i >= index; i--)
node->key[i+1] = node->key[i];
node->key[index] = key;
node->total++;
} else {
BplusTreeNode *child_node = node->child[index];
if (child_node->total == 2*N-1) {
split_child(node, index);
if (key > node->key[index])
index++;
}
insert_nonfull(key, node->child[index]);
}
}
};
//测试代码
int main() {
BplusTree tree;
for (int i = 1; i <= 10; i++)
tree.insert(i);
if (tree.search(5))
cout << "5 is in B+ tree" << endl;
else
cout << "5 is not in B+ tree" << endl;
return 0;
}
//定义B+树节点结构体
class BplusTreeNode {
public $key = array();
public $child = array();
public $total;
public $is_leaf;
}
//定义B+树类
class BplusTree {
private $root;
public function __construct() {
$this->root = NULL;
}
//查询key是否在B+树中
public function search($key) {
if ($this->root == NULL)
return false;
else {
$index = $this->search_index($key, $this->root);
if ($index == $this->root->total)
return false;
else if ($key == $this->root->key[$index])
return true;
else if ($this->root->is_leaf)
return false;
else
return $this->search($key, $this->root->child[$index]);
}
}
//插入key到B+树中
public function insert($key) {
if ($this->root == NULL)
$this->root = new BplusTreeNode();
if ($this->root->total == 2*N-1) {
$new_root = new BplusTreeNode();
$new_root->is_leaf = false;
$new_root->child[0] = $this->root;
$this->root = $new_root;
$this->split_child($this->root, 0);
}
$this->insert_nonfull($key, $this->root);
}
//查找key的插入位置
private function search_index($key, $node) {
$low = 0;
$high = $node->total-1;
while ($low <= $high) {
$mid = intval(($low+$high) / 2);
if ($node->key[$mid] == $key)
return $mid;
else if ($node->key[$mid] > $key)
$high = $mid-1;
else
$low = $mid+1;
}
return $low;
}
//递归查找key是否在B+树中
private function search($key, $node) {
$index = $this->search_index($key, $node);
if ($index == $node->total || $key < $node->key[$index])
return false;
else if ($key == $node->key[$index])
return true;
The above content has 2010 characters. Putting the above into MS Word, there are about 229 words.
There is a certain probability that more than this will be generated when the "regenerate" button is clicked, but there will only be a few more lines and it will not be possible to write out the whole code.