|
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\TrieNode; |
|
12
|
|
|
use Countable; |
|
13
|
|
|
|
|
14
|
|
|
/** |
|
15
|
|
|
* TrieTree |
|
16
|
|
|
* |
|
17
|
|
|
* The TrieTree class is a trie (also called digital tree and sometimes radix tree or prefix tree) |
|
18
|
|
|
* that is used to get in O(m) being m the word length. |
|
19
|
|
|
* It is used in software like word corrector and word suggest. |
|
20
|
|
|
* |
|
21
|
|
|
* @author Siro Diaz Palazon <[email protected]> |
|
22
|
|
|
*/ |
|
23
|
|
|
class TrieTree implements Countable { |
|
24
|
|
|
private $root; |
|
25
|
|
|
private $numWords; |
|
26
|
|
|
private $size; |
|
27
|
|
|
|
|
28
|
|
|
public function __construct() { |
|
29
|
|
|
$this->root = new TrieNode(); |
|
30
|
|
|
$this->numWords = 0; |
|
31
|
|
|
$this->size = 0; |
|
32
|
|
|
} |
|
33
|
|
|
|
|
34
|
|
|
/** |
|
35
|
|
|
* Returns the number of words stored in the trie. |
|
36
|
|
|
* |
|
37
|
|
|
* @return int the number of words. |
|
38
|
|
|
*/ |
|
39
|
|
|
public function numWords() : int { |
|
40
|
|
|
return $this->numWords; |
|
41
|
|
|
} |
|
42
|
|
|
|
|
43
|
|
|
/** |
|
44
|
|
|
* Returns true if the tree is empty. Number of prefixes is 0. |
|
45
|
|
|
* |
|
46
|
|
|
* @return bool true if empty. |
|
47
|
|
|
*/ |
|
48
|
|
|
public function empty() : bool { |
|
49
|
|
|
return $this->size === 0; |
|
50
|
|
|
} |
|
51
|
|
|
|
|
52
|
|
|
/** |
|
53
|
|
|
* Returns the number of prefixes that are contained in the trie. |
|
54
|
|
|
* |
|
55
|
|
|
* @return int the num of prefixes. |
|
56
|
|
|
*/ |
|
57
|
|
|
public function size() : int { |
|
58
|
|
|
return $this->size; |
|
59
|
|
|
} |
|
60
|
|
|
|
|
61
|
|
|
/** |
|
62
|
|
|
* Inserts a new word in the tree. If the word exists it doesn't do nothing. |
|
63
|
|
|
* |
|
64
|
|
|
* @param string $word the word to be added. |
|
65
|
|
|
*/ |
|
66
|
|
|
public function add($word) { |
|
67
|
|
|
$word = trim($word); |
|
68
|
|
|
if(mb_strlen($word) === 0) { |
|
69
|
|
|
return; |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
$current = &$this->root; |
|
73
|
|
|
for($i = 0; $i < mb_strlen($word); $i++) { |
|
74
|
|
|
$char = mb_substr($word, $i, 1, 'UTF-8'); |
|
75
|
|
|
if(!isset($current->children[$char])) { |
|
76
|
|
|
if($i === mb_strlen($word) - 1) { |
|
77
|
|
|
$current->children[$char] = new TrieNode($char, true); |
|
78
|
|
|
$current->isWord = true; |
|
79
|
|
|
$this->numWords++; |
|
80
|
|
|
} else { |
|
81
|
|
|
$current->children[$char] = new TrieNode($char, false); |
|
82
|
|
|
} |
|
83
|
|
|
$this->size++; |
|
84
|
|
|
} else { |
|
85
|
|
|
if($i === mb_strlen($word) - 1) { |
|
86
|
|
|
if($current->isWord === false) { |
|
87
|
|
|
$current->isWord = true; |
|
88
|
|
|
$this->numWords++; |
|
89
|
|
|
} |
|
90
|
|
|
} |
|
91
|
|
|
} |
|
92
|
|
|
|
|
93
|
|
|
$current = &$current->children[$char]; |
|
94
|
|
|
} |
|
95
|
|
|
} |
|
96
|
|
|
|
|
97
|
|
|
/** |
|
98
|
|
|
* Returns true if the word is stored in the tree. |
|
99
|
|
|
* |
|
100
|
|
|
* @param string $word The word to check if exists. |
|
101
|
|
|
* @param bool true if is contained. |
|
102
|
|
|
*/ |
|
103
|
|
|
public function contains($word) : bool { |
|
104
|
|
|
$word = trim($word); |
|
105
|
|
|
$wordLength = mb_strlen($word); |
|
106
|
|
|
if($wordLength === 0) { |
|
107
|
|
|
return true; |
|
108
|
|
|
} |
|
109
|
|
|
|
|
110
|
|
|
$i = 0; |
|
111
|
|
|
$found = true; |
|
112
|
|
|
$current = $this->root; |
|
113
|
|
|
while($found && $i < $wordLength) { |
|
114
|
|
|
$char = mb_substr($word, $i, 1); |
|
115
|
|
|
if(isset($current->children[$char])) { |
|
116
|
|
|
$current = $current->children[$char]; |
|
117
|
|
|
} else { |
|
118
|
|
|
$found = false; |
|
119
|
|
|
} |
|
120
|
|
|
$i++; |
|
121
|
|
|
} |
|
122
|
|
|
|
|
123
|
|
|
if($found && $current->isWord) { |
|
124
|
|
|
return true; |
|
125
|
|
|
} |
|
126
|
|
|
|
|
127
|
|
|
return false; |
|
128
|
|
|
} |
|
129
|
|
|
|
|
130
|
|
|
public function getWords() : array { |
|
131
|
|
|
return []; |
|
132
|
|
|
} |
|
133
|
|
|
|
|
134
|
|
|
/** |
|
135
|
|
|
* |
|
136
|
|
|
*/ |
|
137
|
|
|
public function startsWith($prefix) : bool { |
|
|
|
|
|
|
138
|
|
|
return false; |
|
139
|
|
|
} |
|
140
|
|
|
|
|
141
|
|
|
/** |
|
142
|
|
|
* Retrieve the node where ends the prefix especified. |
|
143
|
|
|
* |
|
144
|
|
|
* @param string $prefix The prefix to look for. |
|
145
|
|
|
* @return DataStructures\Trees\Nodes\TrieNode|null null if not found. |
|
146
|
|
|
*/ |
|
147
|
|
|
private function getNodeFromPrefix($prefix) { |
|
|
|
|
|
|
148
|
|
|
if($this->size === 0) { |
|
149
|
|
|
return $this->root; |
|
|
|
|
|
|
150
|
|
|
} |
|
151
|
|
|
|
|
152
|
|
|
$i = 0; |
|
153
|
|
|
$current = $this->root; |
|
154
|
|
|
$prefixLength = mb_strlen(trim($prefix)); |
|
155
|
|
|
while($i < $prefixLength) { |
|
156
|
|
|
$char = mb_substr($prefix, $i, 1, 'UTF-8'); |
|
157
|
|
|
if(!isset($current->children[$char])) { |
|
158
|
|
|
return null; |
|
159
|
|
|
} |
|
160
|
|
|
$current = $current->children[$char]; |
|
161
|
|
|
$i++; |
|
162
|
|
|
} |
|
163
|
|
|
|
|
164
|
|
|
return $current; |
|
165
|
|
|
} |
|
166
|
|
|
|
|
167
|
|
|
/** |
|
168
|
|
|
* Gets the number of words stored in the tree. |
|
169
|
|
|
* |
|
170
|
|
|
* @return int The word count. |
|
171
|
|
|
*/ |
|
172
|
|
|
public function wordCount() : int { |
|
173
|
|
|
return $this->numWords; |
|
174
|
|
|
} |
|
175
|
|
|
|
|
176
|
|
|
/** |
|
177
|
|
|
* Gets the number of prefixes stored in the tree. |
|
178
|
|
|
* |
|
179
|
|
|
* @return int The word count. |
|
180
|
|
|
*/ |
|
181
|
|
|
public function count() : int { |
|
182
|
|
|
return $this->size(); |
|
183
|
|
|
} |
|
184
|
|
|
} |
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.