|
1
|
|
|
<?php |
|
2
|
|
|
/** |
|
3
|
|
|
* DataStructures for PHP |
|
4
|
|
|
* |
|
5
|
|
|
* @link https://github.com/SiroDiaz/DataStructures |
|
6
|
|
|
* @copyright Copyright (c) 2017 Siro Díaz Palazón |
|
7
|
|
|
* @license https://github.com/SiroDiaz/DataStructures/blob/master/README.md (MIT License) |
|
8
|
|
|
*/ |
|
9
|
|
|
namespace DataStructures\Trees; |
|
10
|
|
|
|
|
11
|
|
|
use DataStructures\Trees\Nodes\BSTNode; |
|
12
|
|
|
use DataStructures\Trees\Interfaces\BinaryNodeInterface; |
|
13
|
|
|
use DataStructures\Trees\BinaryTreeAbstract; |
|
14
|
|
|
|
|
15
|
|
|
/** |
|
16
|
|
|
* BinarySearchTree |
|
17
|
|
|
* |
|
18
|
|
|
* Represents a BST actions that can be realized. |
|
19
|
|
|
* At the beginning root is null and it can grow up to a O(n) in search, |
|
20
|
|
|
* delete and insert (in worst case). In best cases it will be O(log n). |
|
21
|
|
|
* |
|
22
|
|
|
* @author Siro Diaz Palazon <[email protected]> |
|
23
|
|
|
*/ |
|
24
|
|
|
class BinarySearchTree extends BinaryTreeAbstract { |
|
25
|
|
|
|
|
26
|
|
|
public function __construct() { |
|
27
|
|
|
$this->root = null; |
|
28
|
|
|
$this->size = 0; |
|
29
|
|
|
} |
|
30
|
|
|
|
|
31
|
|
|
/** |
|
32
|
|
|
* Inserts data in the correct position. |
|
33
|
|
|
* |
|
34
|
|
|
* @param integer|string $key the key used to store. |
|
35
|
|
|
* @param mixed $data the data to store. |
|
36
|
|
|
* @param bool $update if false the node isn't updated |
|
37
|
|
|
* else if the key matches is updated. |
|
38
|
|
|
*/ |
|
39
|
|
|
public function put($key, $data, $update = false) { |
|
40
|
|
|
$newNode = new BSTNode($key, $data); |
|
41
|
|
|
|
|
42
|
|
|
if($this->root === null) { |
|
43
|
|
|
$this->root = &$newNode; |
|
44
|
|
|
$this->size++; |
|
45
|
|
|
return; |
|
46
|
|
|
} |
|
47
|
|
|
|
|
48
|
|
|
$parentNode = null; |
|
49
|
|
|
$current = &$this->root; |
|
50
|
|
|
while($current !== null) { |
|
51
|
|
|
$parentNode = &$current; |
|
52
|
|
|
if($key < $current->key) { |
|
53
|
|
|
$current = &$current->left; |
|
54
|
|
|
} else if($key > $current->key) { |
|
55
|
|
|
$current = &$current->right; |
|
56
|
|
|
} else { |
|
57
|
|
|
if($update) { |
|
58
|
|
|
$current->data = $data; |
|
59
|
|
|
} |
|
60
|
|
|
return; |
|
61
|
|
|
} |
|
62
|
|
|
} |
|
63
|
|
|
|
|
64
|
|
|
$newNode->parent = &$parentNode; |
|
65
|
|
|
if($key < $parentNode->key) { |
|
66
|
|
|
$parentNode->left = &$newNode; |
|
67
|
|
|
} else { |
|
68
|
|
|
$parentNode->right = &$newNode; |
|
69
|
|
|
} |
|
70
|
|
|
|
|
71
|
|
|
$this->size++; |
|
72
|
|
|
} |
|
73
|
|
|
|
|
74
|
|
|
/** |
|
75
|
|
|
* Creates a new node or updates it if already exists. |
|
76
|
|
|
* |
|
77
|
|
|
* @param int|string $key the key. |
|
78
|
|
|
* @param mixed $data the data to be stored. |
|
79
|
|
|
*/ |
|
80
|
|
|
public function putOrUpdate($key, $data) { |
|
81
|
|
|
$this->put($key, $data, true); |
|
82
|
|
|
} |
|
83
|
|
|
|
|
84
|
|
|
/** |
|
85
|
|
|
* Deletes the node with the maximum key and returns it. The most right and more bottom. |
|
86
|
|
|
* |
|
87
|
|
|
* @param DataStructures\Trees\Nodes\BSTNode|null if null takes the root. |
|
88
|
|
|
* @return DataStructures\Trees\Nodes\BSTNode|null the maximum node or |
|
89
|
|
|
* null if the tree is empty. |
|
90
|
|
|
*/ |
|
91
|
|
|
public function delete($key) { |
|
92
|
|
|
$deleteNode = $this->search($key); |
|
93
|
|
|
if($deleteNode !== null) { |
|
94
|
|
|
$this->_delete($deleteNode); |
|
95
|
|
|
return $deleteNode; |
|
96
|
|
|
} |
|
97
|
|
|
|
|
98
|
|
|
return null; |
|
99
|
|
|
} |
|
100
|
|
|
|
|
101
|
|
|
/** |
|
102
|
|
|
* Deletes the selected node if is not null and returns the node |
|
103
|
|
|
* that replaces the deleted node. Also decrease the size of tree. |
|
104
|
|
|
* |
|
105
|
|
|
* @param DataStructures\Trees\Nodes\BSTNode|null The node to be deleted. |
|
106
|
|
|
* @return the node that replaces the deleted. |
|
107
|
|
|
*/ |
|
108
|
|
|
protected function _delete(BinaryNodeInterface &$node) { |
|
109
|
|
|
if($node !== null) { |
|
110
|
|
|
$nodeToReturn = null; |
|
111
|
|
|
if($node->left === null) { |
|
|
|
|
|
|
112
|
|
|
$nodeToReturn = $this->replace($node, $node->right); |
|
|
|
|
|
|
113
|
|
|
} else if($node->right === null) { |
|
|
|
|
|
|
114
|
|
|
$nodeToReturn = $this->replace($node, $node->left); |
|
|
|
|
|
|
115
|
|
|
} else { |
|
116
|
|
|
$successorNode = $this->getMinNode($node->right); |
|
|
|
|
|
|
117
|
|
|
if($successorNode->parent !== $node) { |
|
118
|
|
|
$this->replace($successorNode, $successorNode->right); |
|
119
|
|
|
$successorNode->right = &$node->right; |
|
|
|
|
|
|
120
|
|
|
$successorNode->right->parent = &$successorNode; |
|
121
|
|
|
} |
|
122
|
|
|
|
|
123
|
|
|
$this->replace($node, $successorNode); |
|
124
|
|
|
$successorNode->left = &$node->left; |
|
125
|
|
|
$successorNode->left->parent = &$successorNode; |
|
126
|
|
|
$nodeToReturn = &$successorNode; |
|
127
|
|
|
} |
|
128
|
|
|
|
|
129
|
|
|
$this->size--; |
|
130
|
|
|
return $nodeToReturn; |
|
131
|
|
|
} |
|
132
|
|
|
|
|
133
|
|
|
return null; |
|
134
|
|
|
} |
|
135
|
|
|
|
|
136
|
|
|
/** |
|
137
|
|
|
* Traverse in preorder. This is: first visit the root, then |
|
138
|
|
|
* the left subtree and finally the right subtree. |
|
139
|
|
|
* |
|
140
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
141
|
|
|
* node. |
|
142
|
|
|
*/ |
|
143
|
|
|
public function preorder(Callable $callback = null) { |
|
144
|
|
|
$this->_preorder($this->root, $callback); |
|
145
|
|
|
} |
|
146
|
|
|
|
|
147
|
|
|
/** |
|
148
|
|
|
* Private preorder traverse method that is recursive and is called by |
|
149
|
|
|
* the public preorder method. |
|
150
|
|
|
* |
|
151
|
|
|
* @param DataStructures\Trees\Nodes\BSTNode|null $node. |
|
|
|
|
|
|
152
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
153
|
|
|
* node. |
|
154
|
|
|
*/ |
|
155
|
|
View Code Duplication |
private function _preorder($node, Callable $callback = null) { |
|
|
|
|
|
|
156
|
|
|
if($node === null) { |
|
157
|
|
|
return; |
|
158
|
|
|
} |
|
159
|
|
|
if($callback !== null) { |
|
160
|
|
|
call_user_func($callback, $node); |
|
161
|
|
|
} |
|
162
|
|
|
$this->_preorder($node->left, $callback); |
|
163
|
|
|
$this->_preorder($node->right, $callback); |
|
164
|
|
|
} |
|
165
|
|
|
|
|
166
|
|
|
/** |
|
167
|
|
|
* Traverse in inorder. This is: first visit the left subtree, |
|
168
|
|
|
* then the root and finally the right subtree. |
|
169
|
|
|
* |
|
170
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
171
|
|
|
* node. |
|
172
|
|
|
*/ |
|
173
|
|
|
public function inorder(Callable $callback = null) { |
|
|
|
|
|
|
174
|
|
|
$this->_inorder($this->root); |
|
175
|
|
|
} |
|
176
|
|
|
|
|
177
|
|
|
/** |
|
178
|
|
|
* Private inorder traverse method that is recursive and is called by |
|
179
|
|
|
* the public inorder method. |
|
180
|
|
|
* |
|
181
|
|
|
* @param DataStructures\Trees\Nodes\BSTNode|null $node. |
|
|
|
|
|
|
182
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
183
|
|
|
* node. |
|
184
|
|
|
*/ |
|
185
|
|
View Code Duplication |
private function _inorder($node, Callable $callback = null) { |
|
|
|
|
|
|
186
|
|
|
if($node === null) { |
|
187
|
|
|
return; |
|
188
|
|
|
} |
|
189
|
|
|
|
|
190
|
|
|
$this->_inorder($node->left, $callback); |
|
191
|
|
|
if($callback !== null) { |
|
192
|
|
|
call_user_func($callback, $node); |
|
193
|
|
|
} |
|
194
|
|
|
$this->_inorder($node->right, $callback); |
|
195
|
|
|
} |
|
196
|
|
|
|
|
197
|
|
|
/** |
|
198
|
|
|
* Traverse in postorder. This is: first visit the left subtree, |
|
199
|
|
|
* then the right subtree and finally the root. |
|
200
|
|
|
* |
|
201
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
202
|
|
|
* node. |
|
203
|
|
|
*/ |
|
204
|
|
|
public function postorder(Callable $callback = null) { |
|
205
|
|
|
$this->_postorder($this->root, $callback); |
|
206
|
|
|
} |
|
207
|
|
|
|
|
208
|
|
|
/** |
|
209
|
|
|
* Private postorder traverse method that is recursive and is called by |
|
210
|
|
|
* the public postorder method. |
|
211
|
|
|
* |
|
212
|
|
|
* @param DataStructures\Trees\Nodes\BSTNode|null $node. |
|
|
|
|
|
|
213
|
|
|
* @param Callable|null $callback the callback function to apply to each |
|
214
|
|
|
* node. |
|
215
|
|
|
*/ |
|
216
|
|
View Code Duplication |
private function _postorder($node, Callable $callback = null) { |
|
|
|
|
|
|
217
|
|
|
if($node === null) { |
|
218
|
|
|
return; |
|
219
|
|
|
} |
|
220
|
|
|
$this->_postorder($node->left, $callback); |
|
221
|
|
|
$this->_postorder($node->right, $callback); |
|
222
|
|
|
if($callback !== null) { |
|
223
|
|
|
call_user_func($callback, $node); |
|
224
|
|
|
} |
|
225
|
|
|
} |
|
226
|
|
|
} |
If you access a property on an interface, you most likely code against a concrete implementation of the interface.
Available Fixes
Adding an additional type check:
Changing the type hint: