1 |
package com.jwetherell.algorithms.data_structures;
|
2 |
|
3 |
/*
|
4 |
* Borrowed from
|
5 |
* https://github.com/phishman3579/java-algorithms-implementation
|
6 |
*
|
7 |
* Only adjustment is
|
8 |
* public XYZPoint(double latitude, double longitude) { //create point from lat/lng pair
|
9 |
*
|
10 |
*/
|
11 |
|
12 |
import java.util.ArrayList;
|
13 |
import java.util.Collection;
|
14 |
import java.util.Collections;
|
15 |
import java.util.Comparator;
|
16 |
import java.util.HashSet;
|
17 |
import java.util.List;
|
18 |
import java.util.Set;
|
19 |
import java.util.TreeSet;
|
20 |
|
21 |
/**
|
22 |
* A k-d tree (short for k-dimensional tree) is a space-partitioning data
|
23 |
* structure for organizing points in a k-dimensional space. k-d trees are a
|
24 |
* useful data structure for several applications, such as searches involving a
|
25 |
* multidimensional search key (e.g. range searches and nearest neighbor
|
26 |
* searches). k-d trees are a special case of binary space partitioning trees.
|
27 |
*
|
28 |
* http://en.wikipedia.org/wiki/K-d_tree
|
29 |
*
|
30 |
* @author Justin Wetherell <phishman3579@gmail.com>
|
31 |
*/
|
32 |
public class KdTree<T extends KdTree.XYZPoint> {
|
33 |
|
34 |
private int k = 3;
|
35 |
private KdNode root = null;
|
36 |
|
37 |
private static final Comparator<XYZPoint> X_COMPARATOR = new Comparator<XYZPoint>() {
|
38 |
/**
|
39 |
* {@inheritDoc}
|
40 |
*/
|
41 |
@Override
|
42 |
public int compare(XYZPoint o1, XYZPoint o2) {
|
43 |
if (o1.x < o2.x)
|
44 |
return -1;
|
45 |
if (o1.x > o2.x)
|
46 |
return 1;
|
47 |
return 0;
|
48 |
}
|
49 |
};
|
50 |
|
51 |
private static final Comparator<XYZPoint> Y_COMPARATOR = new Comparator<XYZPoint>() {
|
52 |
/**
|
53 |
* {@inheritDoc}
|
54 |
*/
|
55 |
@Override
|
56 |
public int compare(XYZPoint o1, XYZPoint o2) {
|
57 |
if (o1.y < o2.y)
|
58 |
return -1;
|
59 |
if (o1.y > o2.y)
|
60 |
return 1;
|
61 |
return 0;
|
62 |
}
|
63 |
};
|
64 |
|
65 |
private static final Comparator<XYZPoint> Z_COMPARATOR = new Comparator<XYZPoint>() {
|
66 |
/**
|
67 |
* {@inheritDoc}
|
68 |
*/
|
69 |
@Override
|
70 |
public int compare(XYZPoint o1, XYZPoint o2) {
|
71 |
if (o1.z < o2.z)
|
72 |
return -1;
|
73 |
if (o1.z > o2.z)
|
74 |
return 1;
|
75 |
return 0;
|
76 |
}
|
77 |
};
|
78 |
|
79 |
protected static final int X_AXIS = 0;
|
80 |
protected static final int Y_AXIS = 1;
|
81 |
protected static final int Z_AXIS = 2;
|
82 |
|
83 |
/**
|
84 |
* Default constructor.
|
85 |
*/
|
86 |
public KdTree() { }
|
87 |
|
88 |
/**
|
89 |
* Constructor for creating a more balanced tree. It uses the
|
90 |
* "median of points" algorithm.
|
91 |
*
|
92 |
* @param list
|
93 |
* of XYZPoints.
|
94 |
*/
|
95 |
public KdTree(List<XYZPoint> list) {
|
96 |
root = createNode(list, k, 0);
|
97 |
}
|
98 |
|
99 |
/**
|
100 |
* Constructor for creating a more balanced tree. It uses the
|
101 |
* "median of points" algorithm.
|
102 |
*
|
103 |
* @param list
|
104 |
* of XYZPoints.
|
105 |
* @param k
|
106 |
* of the tree.
|
107 |
*/
|
108 |
public KdTree(List<XYZPoint> list, int k) {
|
109 |
root = createNode(list, k, 0);
|
110 |
}
|
111 |
|
112 |
/**
|
113 |
* Create node from list of XYZPoints.
|
114 |
*
|
115 |
* @param list
|
116 |
* of XYZPoints.
|
117 |
* @param k
|
118 |
* of the tree.
|
119 |
* @param depth
|
120 |
* depth of the node.
|
121 |
* @return node created.
|
122 |
*/
|
123 |
private static KdNode createNode(List<XYZPoint> list, int k, int depth) {
|
124 |
if (list == null || list.size() == 0)
|
125 |
return null;
|
126 |
|
127 |
int axis = depth % k;
|
128 |
if (axis == X_AXIS)
|
129 |
Collections.sort(list, X_COMPARATOR);
|
130 |
else if (axis == Y_AXIS)
|
131 |
Collections.sort(list, Y_COMPARATOR);
|
132 |
else
|
133 |
Collections.sort(list, Z_COMPARATOR);
|
134 |
|
135 |
KdNode node = null;
|
136 |
List<XYZPoint> less = new ArrayList<XYZPoint>(list.size());
|
137 |
List<XYZPoint> more = new ArrayList<XYZPoint>(list.size());
|
138 |
if (list.size() > 0) {
|
139 |
int medianIndex = list.size() / 2;
|
140 |
node = new KdNode(list.get(medianIndex), k, depth);
|
141 |
// Process list to see where each non-median point lies
|
142 |
for (int i = 0; i < list.size(); i++) {
|
143 |
if (i == medianIndex)
|
144 |
continue;
|
145 |
XYZPoint p = list.get(i);
|
146 |
// Cannot assume points before the median are less since they could be equal
|
147 |
if (KdNode.compareTo(depth, k, p, node.id) <= 0) {
|
148 |
less.add(p);
|
149 |
} else {
|
150 |
more.add(p);
|
151 |
}
|
152 |
}
|
153 |
|
154 |
if ((medianIndex - 1) >= 0 && less.size() > 0) {
|
155 |
node.lesser = createNode(less, k, depth + 1);
|
156 |
node.lesser.parent = node;
|
157 |
}
|
158 |
|
159 |
if ((medianIndex + 1) <= (list.size() - 1) && more.size() > 0) {
|
160 |
node.greater = createNode(more, k, depth + 1);
|
161 |
node.greater.parent = node;
|
162 |
}
|
163 |
}
|
164 |
|
165 |
return node;
|
166 |
}
|
167 |
|
168 |
/**
|
169 |
* Add value to the tree. Tree can contain multiple equal values.
|
170 |
*
|
171 |
* @param value
|
172 |
* T to add to the tree.
|
173 |
* @return True if successfully added to tree.
|
174 |
*/
|
175 |
public boolean add(T value) {
|
176 |
if (value == null)
|
177 |
return false;
|
178 |
|
179 |
if (root == null) {
|
180 |
root = new KdNode(value);
|
181 |
return true;
|
182 |
}
|
183 |
|
184 |
KdNode node = root;
|
185 |
while (true) {
|
186 |
if (KdNode.compareTo(node.depth, node.k, value, node.id) <= 0) {
|
187 |
// Lesser
|
188 |
if (node.lesser == null) {
|
189 |
KdNode newNode = new KdNode(value, k, node.depth + 1);
|
190 |
newNode.parent = node;
|
191 |
node.lesser = newNode;
|
192 |
break;
|
193 |
}
|
194 |
node = node.lesser;
|
195 |
} else {
|
196 |
// Greater
|
197 |
if (node.greater == null) {
|
198 |
KdNode newNode = new KdNode(value, k, node.depth + 1);
|
199 |
newNode.parent = node;
|
200 |
node.greater = newNode;
|
201 |
break;
|
202 |
}
|
203 |
node = node.greater;
|
204 |
}
|
205 |
}
|
206 |
|
207 |
return true;
|
208 |
}
|
209 |
|
210 |
/**
|
211 |
* Does the tree contain the value.
|
212 |
*
|
213 |
* @param value
|
214 |
* T to locate in the tree.
|
215 |
* @return True if tree contains value.
|
216 |
*/
|
217 |
public boolean contains(T value) {
|
218 |
if (value == null || root == null)
|
219 |
return false;
|
220 |
|
221 |
KdNode node = getNode(this, value);
|
222 |
return (node != null);
|
223 |
}
|
224 |
|
225 |
/**
|
226 |
* Locate T in the tree.
|
227 |
*
|
228 |
* @param tree
|
229 |
* to search.
|
230 |
* @param value
|
231 |
* to search for.
|
232 |
* @return KdNode or NULL if not found
|
233 |
*/
|
234 |
private static final <T extends KdTree.XYZPoint> KdNode getNode(KdTree<T> tree, T value) {
|
235 |
if (tree == null || tree.root == null || value == null)
|
236 |
return null;
|
237 |
|
238 |
KdNode node = tree.root;
|
239 |
while (true) {
|
240 |
if (node.id.equals(value)) {
|
241 |
return node;
|
242 |
} else if (KdNode.compareTo(node.depth, node.k, value, node.id) <= 0) {
|
243 |
// Lesser
|
244 |
if (node.lesser == null) {
|
245 |
return null;
|
246 |
}
|
247 |
node = node.lesser;
|
248 |
} else {
|
249 |
// Greater
|
250 |
if (node.greater == null) {
|
251 |
return null;
|
252 |
}
|
253 |
node = node.greater;
|
254 |
}
|
255 |
}
|
256 |
}
|
257 |
|
258 |
/**
|
259 |
* Remove first occurrence of value in the tree.
|
260 |
*
|
261 |
* @param value
|
262 |
* T to remove from the tree.
|
263 |
* @return True if value was removed from the tree.
|
264 |
*/
|
265 |
public boolean remove(T value) {
|
266 |
if (value == null || root == null)
|
267 |
return false;
|
268 |
|
269 |
KdNode node = getNode(this, value);
|
270 |
if (node == null)
|
271 |
return false;
|
272 |
|
273 |
KdNode parent = node.parent;
|
274 |
if (parent != null) {
|
275 |
if (parent.lesser != null && node.equals(parent.lesser)) {
|
276 |
List<XYZPoint> nodes = getTree(node);
|
277 |
if (nodes.size() > 0) {
|
278 |
parent.lesser = createNode(nodes, node.k, node.depth);
|
279 |
if (parent.lesser != null) {
|
280 |
parent.lesser.parent = parent;
|
281 |
}
|
282 |
} else {
|
283 |
parent.lesser = null;
|
284 |
}
|
285 |
} else {
|
286 |
List<XYZPoint> nodes = getTree(node);
|
287 |
if (nodes.size() > 0) {
|
288 |
parent.greater = createNode(nodes, node.k, node.depth);
|
289 |
if (parent.greater != null) {
|
290 |
parent.greater.parent = parent;
|
291 |
}
|
292 |
} else {
|
293 |
parent.greater = null;
|
294 |
}
|
295 |
}
|
296 |
} else {
|
297 |
// root
|
298 |
List<XYZPoint> nodes = getTree(node);
|
299 |
if (nodes.size() > 0)
|
300 |
root = createNode(nodes, node.k, node.depth);
|
301 |
else
|
302 |
root = null;
|
303 |
}
|
304 |
|
305 |
return true;
|
306 |
}
|
307 |
|
308 |
/**
|
309 |
* Get the (sub) tree rooted at root.
|
310 |
*
|
311 |
* @param root
|
312 |
* of tree to get nodes for.
|
313 |
* @return points in (sub) tree, not including root.
|
314 |
*/
|
315 |
private static final List<XYZPoint> getTree(KdNode root) {
|
316 |
List<XYZPoint> list = new ArrayList<XYZPoint>();
|
317 |
if (root == null)
|
318 |
return list;
|
319 |
|
320 |
if (root.lesser != null) {
|
321 |
list.add(root.lesser.id);
|
322 |
list.addAll(getTree(root.lesser));
|
323 |
}
|
324 |
if (root.greater != null) {
|
325 |
list.add(root.greater.id);
|
326 |
list.addAll(getTree(root.greater));
|
327 |
}
|
328 |
|
329 |
return list;
|
330 |
}
|
331 |
|
332 |
/**
|
333 |
* K Nearest Neighbor search
|
334 |
*
|
335 |
* @param K
|
336 |
* Number of neighbors to retrieve. Can return more than K, if
|
337 |
* last nodes are equal distances.
|
338 |
* @param value
|
339 |
* to find neighbors of.
|
340 |
* @return Collection of T neighbors.
|
341 |
*/
|
342 |
@SuppressWarnings("unchecked")
|
343 |
public Collection<T> nearestNeighbourSearch(int K, T value) {
|
344 |
if (value == null || root == null)
|
345 |
return Collections.EMPTY_LIST;
|
346 |
|
347 |
// Map used for results
|
348 |
TreeSet<KdNode> results = new TreeSet<KdNode>(new EuclideanComparator(value));
|
349 |
|
350 |
// Find the closest leaf node
|
351 |
KdNode prev = null;
|
352 |
KdNode node = root;
|
353 |
while (node != null) {
|
354 |
if (KdNode.compareTo(node.depth, node.k, value, node.id) <= 0) {
|
355 |
// Lesser
|
356 |
prev = node;
|
357 |
node = node.lesser;
|
358 |
} else {
|
359 |
// Greater
|
360 |
prev = node;
|
361 |
node = node.greater;
|
362 |
}
|
363 |
}
|
364 |
KdNode leaf = prev;
|
365 |
|
366 |
if (leaf != null) {
|
367 |
// Used to not re-examine nodes
|
368 |
Set<KdNode> examined = new HashSet<KdNode>();
|
369 |
|
370 |
// Go up the tree, looking for better solutions
|
371 |
node = leaf;
|
372 |
while (node != null) {
|
373 |
// Search node
|
374 |
searchNode(value, node, K, results, examined);
|
375 |
node = node.parent;
|
376 |
}
|
377 |
}
|
378 |
|
379 |
// Load up the collection of the results
|
380 |
Collection<T> collection = new ArrayList<T>(K);
|
381 |
for (KdNode kdNode : results)
|
382 |
collection.add((T) kdNode.id);
|
383 |
return collection;
|
384 |
}
|
385 |
|
386 |
private static final <T extends KdTree.XYZPoint> void searchNode(T value, KdNode node, int K, TreeSet<KdNode> results, Set<KdNode> examined) {
|
387 |
examined.add(node);
|
388 |
|
389 |
// Search node
|
390 |
KdNode lastNode = null;
|
391 |
Double lastDistance = Double.MAX_VALUE;
|
392 |
if (results.size() > 0) {
|
393 |
lastNode = results.last();
|
394 |
lastDistance = lastNode.id.euclideanDistance(value);
|
395 |
}
|
396 |
Double nodeDistance = node.id.euclideanDistance(value);
|
397 |
if (nodeDistance.compareTo(lastDistance) < 0) {
|
398 |
if (results.size() == K && lastNode != null)
|
399 |
results.remove(lastNode);
|
400 |
results.add(node);
|
401 |
} else if (nodeDistance.equals(lastDistance)) {
|
402 |
results.add(node);
|
403 |
} else if (results.size() < K) {
|
404 |
results.add(node);
|
405 |
}
|
406 |
lastNode = results.last();
|
407 |
lastDistance = lastNode.id.euclideanDistance(value);
|
408 |
|
409 |
int axis = node.depth % node.k;
|
410 |
KdNode lesser = node.lesser;
|
411 |
KdNode greater = node.greater;
|
412 |
|
413 |
// Search children branches, if axis aligned distance is less than
|
414 |
// current distance
|
415 |
if (lesser != null && !examined.contains(lesser)) {
|
416 |
examined.add(lesser);
|
417 |
|
418 |
double nodePoint = Double.MIN_VALUE;
|
419 |
double valuePlusDistance = Double.MIN_VALUE;
|
420 |
if (axis == X_AXIS) {
|
421 |
nodePoint = node.id.x;
|
422 |
valuePlusDistance = value.x - lastDistance;
|
423 |
} else if (axis == Y_AXIS) {
|
424 |
nodePoint = node.id.y;
|
425 |
valuePlusDistance = value.y - lastDistance;
|
426 |
} else {
|
427 |
nodePoint = node.id.z;
|
428 |
valuePlusDistance = value.z - lastDistance;
|
429 |
}
|
430 |
boolean lineIntersectsCube = ((valuePlusDistance <= nodePoint) ? true : false);
|
431 |
|
432 |
// Continue down lesser branch
|
433 |
if (lineIntersectsCube)
|
434 |
searchNode(value, lesser, K, results, examined);
|
435 |
}
|
436 |
if (greater != null && !examined.contains(greater)) {
|
437 |
examined.add(greater);
|
438 |
|
439 |
double nodePoint = Double.MIN_VALUE;
|
440 |
double valuePlusDistance = Double.MIN_VALUE;
|
441 |
if (axis == X_AXIS) {
|
442 |
nodePoint = node.id.x;
|
443 |
valuePlusDistance = value.x + lastDistance;
|
444 |
} else if (axis == Y_AXIS) {
|
445 |
nodePoint = node.id.y;
|
446 |
valuePlusDistance = value.y + lastDistance;
|
447 |
} else {
|
448 |
nodePoint = node.id.z;
|
449 |
valuePlusDistance = value.z + lastDistance;
|
450 |
}
|
451 |
boolean lineIntersectsCube = ((valuePlusDistance >= nodePoint) ? true : false);
|
452 |
|
453 |
// Continue down greater branch
|
454 |
if (lineIntersectsCube)
|
455 |
searchNode(value, greater, K, results, examined);
|
456 |
}
|
457 |
}
|
458 |
|
459 |
/**
|
460 |
* {@inheritDoc}
|
461 |
*/
|
462 |
@Override
|
463 |
public String toString() {
|
464 |
return TreePrinter.getString(this);
|
465 |
}
|
466 |
|
467 |
protected static class EuclideanComparator implements Comparator<KdNode> {
|
468 |
|
469 |
private final XYZPoint point;
|
470 |
|
471 |
public EuclideanComparator(XYZPoint point) {
|
472 |
this.point = point;
|
473 |
}
|
474 |
|
475 |
/**
|
476 |
* {@inheritDoc}
|
477 |
*/
|
478 |
@Override
|
479 |
public int compare(KdNode o1, KdNode o2) {
|
480 |
Double d1 = point.euclideanDistance(o1.id);
|
481 |
Double d2 = point.euclideanDistance(o2.id);
|
482 |
if (d1.compareTo(d2) < 0)
|
483 |
return -1;
|
484 |
else if (d2.compareTo(d1) < 0)
|
485 |
return 1;
|
486 |
return o1.id.compareTo(o2.id);
|
487 |
}
|
488 |
}
|
489 |
|
490 |
public static class KdNode implements Comparable<KdNode> {
|
491 |
|
492 |
private final XYZPoint id;
|
493 |
private final int k;
|
494 |
private final int depth;
|
495 |
|
496 |
private KdNode parent = null;
|
497 |
private KdNode lesser = null;
|
498 |
private KdNode greater = null;
|
499 |
|
500 |
public KdNode(XYZPoint id) {
|
501 |
this.id = id;
|
502 |
this.k = 3;
|
503 |
this.depth = 0;
|
504 |
}
|
505 |
|
506 |
public KdNode(XYZPoint id, int k, int depth) {
|
507 |
this.id = id;
|
508 |
this.k = k;
|
509 |
this.depth = depth;
|
510 |
}
|
511 |
|
512 |
public static int compareTo(int depth, int k, XYZPoint o1, XYZPoint o2) {
|
513 |
int axis = depth % k;
|
514 |
if (axis == X_AXIS)
|
515 |
return X_COMPARATOR.compare(o1, o2);
|
516 |
if (axis == Y_AXIS)
|
517 |
return Y_COMPARATOR.compare(o1, o2);
|
518 |
return Z_COMPARATOR.compare(o1, o2);
|
519 |
}
|
520 |
|
521 |
/**
|
522 |
* {@inheritDoc}
|
523 |
*/
|
524 |
@Override
|
525 |
public int hashCode() {
|
526 |
return 31 * (this.k + this.depth + this.id.hashCode());
|
527 |
}
|
528 |
|
529 |
/**
|
530 |
* {@inheritDoc}
|
531 |
*/
|
532 |
@Override
|
533 |
public boolean equals(Object obj) {
|
534 |
if (obj == null)
|
535 |
return false;
|
536 |
if (!(obj instanceof KdNode))
|
537 |
return false;
|
538 |
|
539 |
KdNode kdNode = (KdNode) obj;
|
540 |
if (this.compareTo(kdNode) == 0)
|
541 |
return true;
|
542 |
return false;
|
543 |
}
|
544 |
|
545 |
/**
|
546 |
* {@inheritDoc}
|
547 |
*/
|
548 |
@Override
|
549 |
public int compareTo(KdNode o) {
|
550 |
return compareTo(depth, k, this.id, o.id);
|
551 |
}
|
552 |
|
553 |
/**
|
554 |
* {@inheritDoc}
|
555 |
*/
|
556 |
@Override
|
557 |
public String toString() {
|
558 |
StringBuilder builder = new StringBuilder();
|
559 |
builder.append("k=").append(k);
|
560 |
builder.append(" depth=").append(depth);
|
561 |
builder.append(" id=").append(id.toString());
|
562 |
return builder.toString();
|
563 |
}
|
564 |
}
|
565 |
|
566 |
public static class XYZPoint implements Comparable<XYZPoint> {
|
567 |
|
568 |
protected final double x;
|
569 |
protected final double y;
|
570 |
protected final double z;
|
571 |
|
572 |
/* public XYZPoint(double x, double y) {
|
573 |
this.x = x;
|
574 |
this.y = y;
|
575 |
this.z = 0;
|
576 |
}*/
|
577 |
|
578 |
public XYZPoint(double x, double y, double z) {
|
579 |
this.x = x;
|
580 |
this.y = y;
|
581 |
this.z = z;
|
582 |
}
|
583 |
|
584 |
public XYZPoint(double latitude, double longitude) { //create point from lat/lng pair
|
585 |
this.x = Math.cos(Math.toRadians(latitude)) * Math.cos(Math.toRadians(longitude));
|
586 |
this.y = Math.cos(Math.toRadians(latitude)) * Math.sin(Math.toRadians(longitude));
|
587 |
this.z = Math.sin(Math.toRadians(latitude));
|
588 |
}
|
589 |
|
590 |
public double getX() {
|
591 |
return x;
|
592 |
}
|
593 |
public double getY() {
|
594 |
return y;
|
595 |
}
|
596 |
public double getZ() {
|
597 |
return z;
|
598 |
}
|
599 |
|
600 |
/**
|
601 |
* Computes the Euclidean distance from this point to the other.
|
602 |
*
|
603 |
* @param o1
|
604 |
* other point.
|
605 |
* @return euclidean distance.
|
606 |
*/
|
607 |
public double euclideanDistance(XYZPoint o1) {
|
608 |
return euclideanDistance(o1, this);
|
609 |
}
|
610 |
|
611 |
/**
|
612 |
* Computes the Euclidean distance from one point to the other.
|
613 |
*
|
614 |
* @param o1
|
615 |
* first point.
|
616 |
* @param o2
|
617 |
* second point.
|
618 |
* @return euclidean distance.
|
619 |
*/
|
620 |
private static final double euclideanDistance(XYZPoint o1, XYZPoint o2) {
|
621 |
return Math.sqrt(Math.pow((o1.x - o2.x), 2) + Math.pow((o1.y - o2.y), 2) + Math.pow((o1.z - o2.z), 2));
|
622 |
}
|
623 |
|
624 |
/**
|
625 |
* {@inheritDoc}
|
626 |
*/
|
627 |
@Override
|
628 |
public int hashCode() {
|
629 |
return 31 * (int)(this.x + this.y + this.z);
|
630 |
}
|
631 |
|
632 |
/**
|
633 |
* {@inheritDoc}
|
634 |
*/
|
635 |
@Override
|
636 |
public boolean equals(Object obj) {
|
637 |
if (obj == null)
|
638 |
return false;
|
639 |
if (!(obj instanceof XYZPoint))
|
640 |
return false;
|
641 |
|
642 |
XYZPoint xyzPoint = (XYZPoint) obj;
|
643 |
return compareTo(xyzPoint) == 0;
|
644 |
}
|
645 |
|
646 |
/**
|
647 |
* {@inheritDoc}
|
648 |
*/
|
649 |
@Override
|
650 |
public int compareTo(XYZPoint o) {
|
651 |
int xComp = X_COMPARATOR.compare(this, o);
|
652 |
if (xComp != 0)
|
653 |
return xComp;
|
654 |
int yComp = Y_COMPARATOR.compare(this, o);
|
655 |
if (yComp != 0)
|
656 |
return yComp;
|
657 |
int zComp = Z_COMPARATOR.compare(this, o);
|
658 |
return zComp;
|
659 |
}
|
660 |
|
661 |
/**
|
662 |
* {@inheritDoc}
|
663 |
*/
|
664 |
@Override
|
665 |
public String toString() {
|
666 |
StringBuilder builder = new StringBuilder();
|
667 |
builder.append("(");
|
668 |
builder.append(x).append(", ");
|
669 |
builder.append(y).append(", ");
|
670 |
builder.append(z);
|
671 |
builder.append(")");
|
672 |
return builder.toString();
|
673 |
}
|
674 |
}
|
675 |
|
676 |
protected static class TreePrinter {
|
677 |
|
678 |
public static <T extends XYZPoint> String getString(KdTree<T> tree) {
|
679 |
if (tree.root == null)
|
680 |
return "Tree has no nodes.";
|
681 |
return getString(tree.root, "", true);
|
682 |
}
|
683 |
|
684 |
private static String getString(KdNode node, String prefix, boolean isTail) {
|
685 |
StringBuilder builder = new StringBuilder();
|
686 |
|
687 |
if (node.parent != null) {
|
688 |
String side = "left";
|
689 |
if (node.parent.greater != null && node.id.equals(node.parent.greater.id))
|
690 |
side = "right";
|
691 |
builder.append(prefix + (isTail ? "└── " : "├── ") + "[" + side + "] " + "depth=" + node.depth + " id="
|
692 |
+ node.id + "\n");
|
693 |
} else {
|
694 |
builder.append(prefix + (isTail ? "└── " : "├── ") + "depth=" + node.depth + " id=" + node.id + "\n");
|
695 |
}
|
696 |
List<KdNode> children = null;
|
697 |
if (node.lesser != null || node.greater != null) {
|
698 |
children = new ArrayList<KdNode>(2);
|
699 |
if (node.lesser != null)
|
700 |
children.add(node.lesser);
|
701 |
if (node.greater != null)
|
702 |
children.add(node.greater);
|
703 |
}
|
704 |
if (children != null) {
|
705 |
for (int i = 0; i < children.size() - 1; i++) {
|
706 |
builder.append(getString(children.get(i), prefix + (isTail ? " " : "│ "), false));
|
707 |
}
|
708 |
if (children.size() >= 1) {
|
709 |
builder.append(getString(children.get(children.size() - 1), prefix + (isTail ? " " : "│ "),
|
710 |
true));
|
711 |
}
|
712 |
}
|
713 |
|
714 |
return builder.toString();
|
715 |
}
|
716 |
}
|
717 |
} |