1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
|
<?php
define('I',100000); // define infinite distance
/**
* class to Build Dijkstra model
* To build the class
* Use int to index all the points on the map
* @param int startPoint
* @param array routes[] = array($startPoint,$endPoint,$distance)
* @author Rick.purple
*/
class Dijkstra{
private $intStartPoint;
private $aRoutes = array(); // all possible routes between each two points (single direction)
private $aPoints = array(); // all the points on the map
private $aReds = array();
private $aBlues = array();
private $aComp = array();
private $aDistances = array(); // the closest distance from start point to each points
private $aPathes = array(); // path from each points to its neibor on the best path to the start point
private $aFullPathes; // path from start point to each points
/**
* Build Dijkstra model, find best path and closest distance from start point to each point on the map
* @return null
* @param object $intStartPoint
* @param object $aRoutes
*/
public function __construct($intStartPoint,$aRoutes){
$this->aRoutes = $aRoutes;
$this->intStartPoint = $intStartPoint;
foreach($aRoutes as $aRoute){
if(!in_array($aRoute[0],$this->aPoints)){
$this->aPoints[] = $aRoute[0];
}
if(!in_array($aRoute[1],$this->aPoints)){
$this->aPoints[] = $aRoute[1];
}
}
$this->aReds = array($intStartPoint);
$this->aBlues = $this->array_remove($this->aPoints, $intStartPoint);
foreach($this->aBlues as $intPoint){
$this->aDistances[$intPoint] = I;
}
$this->aDistances[$intStartPoint] = 0;
$this->findPath();
}
/**
* function to get the best path
* @return pathes for each node on the map
*/
public function getPath(){
foreach($this->aPoints as $intPoint){
$this->fillFullPath($intPoint,$intPoint);
}
return $this->aFullPathes;
}
/**
* function to get the closest distance
* @return
*/
public function getDistance(){
return $this->aDistances;
}
public function get_company(){
return $this->aComp;
}
/**
* Remove specified element from array
* @return array
* @param array $arr : array to be processing
* @param array $value : the element to be remove from the array
*/
private function array_remove($arr,$value) {
return array_values(array_diff($arr,array($value)));
}
/**
* Dijkstra algorithm implementation
* @return null
*/
private function findPath(){
while(!empty($this->aBlues)){
$intShortest = I;
foreach($this->aReds as $intRed){
# find possible rounte
foreach($this->aRoutes as $aRoute){
if($intRed == $aRoute[0]){
$aDis[$intRed][$aRoute[1]] = $aRoute[2];
# rewrite distance
$intDistance = $this->aDistances[$intRed] + $aRoute[2];
if($this->aDistances[$aRoute[1]] > $intDistance){
$this->aDistances[$aRoute[1]] = $intDistance;
$this->aComp[$aRoute[1]][$aRoute[2]] = $aRoute[3];
# change the path
if($intRed==$this->intStartPoint ||$intRed==$aRoute[1]){}
else{
$this->aPathes[$aRoute[1]] = $intRed;
}
}
# find the nearest neighbor
if(!in_array($aRoute[1],$this->aReds)&&$aRoute[2]<$intShortest){
$intShortest = $aRoute[2];
$intAddPoint = $aRoute[1];
}
}
}
}
$this->aReds[] = $intAddPoint;
$this->aBlues = $this->array_remove($this->aBlues, $intAddPoint);
}
}
/**
* mid step function to find full path from start point to the end point.
* @return null
* @param int $intEndPoint
* @param int $intMidPoint
*/
private function fillFullPath($intEndPoint,$intMidPoint){
if(isset($this->aPathes[$intMidPoint])){
$this->aFullPathes[$intEndPoint][] = $this->aPathes[$intMidPoint];
$this->fillFullPath($intEndPoint,$this->aPathes[$intMidPoint]);
}
else{
$this->aFullPathes[$intEndPoint][] = $this->intStartPoint;
}
}
}
/*
# Examples
// single direction route path
$aRoutes = array(
array(0,0,0),
array(0,1,10),
array(0,3,30), // use something like array(3,0,20) to define a two way map
array(0,4,100),
array(1,1,0),
array(1,2,50),
array(2,2,0),
array(2,4,10),
array(3,3,0),
array(3,2,20),
array(3,4,60),
array(4,4,0),
);
$oDijk = new Dijkstra(0,$aRoutes); // startPoint = 0
print_r($oDijk->getPath());
print_r($oDijk->getDistance());
*/
?> |
[Algorithme] Dijkstra : plus court chemin
Répondre avec citation
Envoyé par I_believe_in_code
Partager