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b74e26bb | 1 | ;;; avl-tree.el --- balanced binary trees, AVL-trees |
1e38b8ff | 2 | |
73b0cd50 | 3 | ;; Copyright (C) 1995, 2007-2011 Free Software Foundation, Inc. |
1e38b8ff TTN |
4 | |
5 | ;; Author: Per Cederqvist <ceder@lysator.liu.se> | |
3769ddcf TC |
6 | ;; Inge Wallin <inge@lysator.liu.se> |
7 | ;; Thomas Bellman <bellman@lysator.liu.se> | |
8 | ;; Toby Cubitt <toby-predictive@dr-qubit.org> | |
b74e26bb TTN |
9 | ;; Maintainer: FSF |
10 | ;; Created: 10 May 1991 | |
3769ddcf | 11 | ;; Keywords: extensions, data structures, AVL, tree |
1e38b8ff | 12 | |
b74e26bb | 13 | ;; This file is part of GNU Emacs. |
1e38b8ff | 14 | |
d6cba7ae | 15 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
b74e26bb | 16 | ;; it under the terms of the GNU General Public License as published by |
d6cba7ae GM |
17 | ;; the Free Software Foundation, either version 3 of the License, or |
18 | ;; (at your option) any later version. | |
1e38b8ff | 19 | |
b74e26bb TTN |
20 | ;; GNU Emacs is distributed in the hope that it will be useful, |
21 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
22 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
23 | ;; GNU General Public License for more details. | |
1e38b8ff | 24 | |
b74e26bb | 25 | ;; You should have received a copy of the GNU General Public License |
d6cba7ae | 26 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
1e38b8ff | 27 | |
b74e26bb | 28 | ;;; Commentary: |
1e38b8ff | 29 | |
3769ddcf TC |
30 | ;; An AVL tree is a self-balancing binary tree. As such, inserting, |
31 | ;; deleting, and retrieving data from an AVL tree containing n elements | |
32 | ;; is O(log n). It is somewhat more rigidly balanced than other | |
33 | ;; self-balancing binary trees (such as red-black trees and AA trees), | |
34 | ;; making insertion slighty slower, deletion somewhat slower, and | |
35 | ;; retrieval somewhat faster (the asymptotic scaling is of course the | |
36 | ;; same for all types). Thus it may be a good choice when the tree will | |
37 | ;; be relatively static, i.e. data will be retrieved more often than | |
38 | ;; they are modified. | |
39 | ;; | |
40 | ;; Internally, a tree consists of two elements, the root node and the | |
41 | ;; comparison function. The actual tree has a dummy node as its root | |
42 | ;; with the real root in the left pointer, which allows the root node to | |
43 | ;; be treated on a par with all other nodes. | |
b74e26bb TTN |
44 | ;; |
45 | ;; Each node of the tree consists of one data element, one left | |
3769ddcf TC |
46 | ;; sub-tree, one right sub-tree, and a balance count. The latter is the |
47 | ;; difference in depth of the left and right sub-trees. | |
d385b030 | 48 | ;; |
afdd184c SM |
49 | ;; The functions with names of the form "avl-tree--" are intended for |
50 | ;; internal use only. | |
1e38b8ff | 51 | |
b74e26bb TTN |
52 | ;;; Code: |
53 | ||
afdd184c SM |
54 | (eval-when-compile (require 'cl)) |
55 | ||
afdd184c | 56 | |
afdd184c | 57 | |
3769ddcf TC |
58 | ;; ================================================================ |
59 | ;;; Internal functions and macros for use in the AVL tree package | |
d385b030 | 60 | |
1e38b8ff | 61 | |
3769ddcf TC |
62 | ;; ---------------------------------------------------------------- |
63 | ;; Functions and macros handling an AVL tree. | |
afdd184c SM |
64 | |
65 | (defstruct (avl-tree- | |
66 | ;; A tagged list is the pre-defstruct representation. | |
67 | ;; (:type list) | |
68 | :named | |
69 | (:constructor nil) | |
3769ddcf | 70 | (:constructor avl-tree--create (cmpfun)) |
afdd184c SM |
71 | (:predicate avl-tree-p) |
72 | (:copier nil)) | |
73 | (dummyroot (avl-tree--node-create nil nil nil 0)) | |
74 | cmpfun) | |
75 | ||
76 | (defmacro avl-tree--root (tree) | |
1e38b8ff | 77 | ;; Return the root node for an avl-tree. INTERNAL USE ONLY. |
3769ddcf TC |
78 | `(avl-tree--node-left (avl-tree--dummyroot ,tree))) |
79 | ||
afdd184c SM |
80 | (defsetf avl-tree--root (tree) (node) |
81 | `(setf (avl-tree--node-left (avl-tree--dummyroot ,tree)) ,node)) | |
1e38b8ff | 82 | |
3769ddcf TC |
83 | |
84 | ||
1e38b8ff | 85 | ;; ---------------------------------------------------------------- |
3769ddcf | 86 | ;; Functions and macros handling an AVL tree node. |
1e38b8ff | 87 | |
3769ddcf TC |
88 | (defstruct (avl-tree--node |
89 | ;; We force a representation without tag so it matches the | |
90 | ;; pre-defstruct representation. Also we use the underlying | |
91 | ;; representation in the implementation of | |
92 | ;; avl-tree--node-branch. | |
93 | (:type vector) | |
94 | (:constructor nil) | |
95 | (:constructor avl-tree--node-create (left right data balance)) | |
96 | (:copier nil)) | |
97 | left right data balance) | |
1e38b8ff | 98 | |
1e38b8ff | 99 | |
3769ddcf TC |
100 | (defalias 'avl-tree--node-branch 'aref |
101 | ;; This implementation is efficient but breaks the defstruct | |
102 | ;; abstraction. An alternative could be (funcall (aref [avl-tree-left | |
103 | ;; avl-tree-right avl-tree-data] branch) node) | |
104 | "Get value of a branch of a node. | |
105 | NODE is the node, and BRANCH is the branch. | |
106 | 0 for left pointer, 1 for right pointer and 2 for the data.") | |
107 | ||
108 | ||
109 | ;; The funcall/aref trick wouldn't work for the setf method, unless we | |
110 | ;; tried to access the underlying setter function, but this wouldn't be | |
111 | ;; portable either. | |
112 | (defsetf avl-tree--node-branch aset) | |
113 | ||
114 | ||
115 | ||
116 | ;; ---------------------------------------------------------------- | |
117 | ;; Convenience macros | |
1e38b8ff | 118 | |
3769ddcf TC |
119 | (defmacro avl-tree--switch-dir (dir) |
120 | "Return opposite direction to DIR (0 = left, 1 = right)." | |
121 | `(- 1 ,dir)) | |
122 | ||
123 | (defmacro avl-tree--dir-to-sign (dir) | |
124 | "Convert direction (0,1) to sign factor (-1,+1)." | |
125 | `(1- (* 2 ,dir))) | |
126 | ||
127 | (defmacro avl-tree--sign-to-dir (dir) | |
128 | "Convert sign factor (-x,+x) to direction (0,1)." | |
129 | `(if (< ,dir 0) 0 1)) | |
130 | ||
131 | ||
132 | ;; ---------------------------------------------------------------- | |
133 | ;; Deleting data | |
134 | ||
135 | (defun avl-tree--del-balance (node branch dir) | |
136 | "Rebalance a tree after deleting a node. | |
137 | The deletion was done from the left (DIR=0) or right (DIR=1) sub-tree of the | |
138 | left (BRANCH=0) or right (BRANCH=1) child of NODE. | |
139 | Return t if the height of the tree has shrunk." | |
140 | ;; (or is it vice-versa for BRANCH?) | |
afdd184c | 141 | (let ((br (avl-tree--node-branch node branch)) |
3769ddcf TC |
142 | ;; opposite direction: 0,1 -> 1,0 |
143 | (opp (avl-tree--switch-dir dir)) | |
144 | ;; direction 0,1 -> sign factor -1,+1 | |
145 | (sgn (avl-tree--dir-to-sign dir)) | |
146 | p1 b1 p2 b2) | |
1e38b8ff | 147 | (cond |
3769ddcf | 148 | ((> (* sgn (avl-tree--node-balance br)) 0) |
afdd184c | 149 | (setf (avl-tree--node-balance br) 0) |
1e38b8ff TTN |
150 | t) |
151 | ||
afdd184c | 152 | ((= (avl-tree--node-balance br) 0) |
3769ddcf | 153 | (setf (avl-tree--node-balance br) (- sgn)) |
1e38b8ff TTN |
154 | nil) |
155 | ||
b74e26bb TTN |
156 | (t |
157 | ;; Rebalance. | |
3769ddcf | 158 | (setq p1 (avl-tree--node-branch br opp) |
afdd184c | 159 | b1 (avl-tree--node-balance p1)) |
3769ddcf TC |
160 | (if (<= (* sgn b1) 0) |
161 | ;; Single rotation. | |
b74e26bb | 162 | (progn |
3769ddcf TC |
163 | (setf (avl-tree--node-branch br opp) |
164 | (avl-tree--node-branch p1 dir) | |
165 | (avl-tree--node-branch p1 dir) br | |
166 | (avl-tree--node-branch node branch) p1) | |
b74e26bb TTN |
167 | (if (= 0 b1) |
168 | (progn | |
3769ddcf TC |
169 | (setf (avl-tree--node-balance br) (- sgn) |
170 | (avl-tree--node-balance p1) sgn) | |
171 | nil) ; height hasn't changed | |
afdd184c SM |
172 | (setf (avl-tree--node-balance br) 0) |
173 | (setf (avl-tree--node-balance p1) 0) | |
3769ddcf TC |
174 | t)) ; height has changed |
175 | ||
176 | ;; Double rotation. | |
177 | (setf p2 (avl-tree--node-branch p1 dir) | |
178 | b2 (avl-tree--node-balance p2) | |
179 | (avl-tree--node-branch p1 dir) | |
180 | (avl-tree--node-branch p2 opp) | |
181 | (avl-tree--node-branch p2 opp) p1 | |
182 | (avl-tree--node-branch br opp) | |
183 | (avl-tree--node-branch p2 dir) | |
184 | (avl-tree--node-branch p2 dir) br | |
185 | (avl-tree--node-balance br) | |
186 | (if (< (* sgn b2) 0) sgn 0) | |
187 | (avl-tree--node-balance p1) | |
188 | (if (> (* sgn b2) 0) (- sgn) 0) | |
189 | (avl-tree--node-branch node branch) p2 | |
190 | (avl-tree--node-balance p2) 0) | |
b74e26bb | 191 | t))))) |
1e38b8ff | 192 | |
afdd184c SM |
193 | (defun avl-tree--do-del-internal (node branch q) |
194 | (let ((br (avl-tree--node-branch node branch))) | |
195 | (if (avl-tree--node-right br) | |
3769ddcf TC |
196 | (if (avl-tree--do-del-internal br 1 q) |
197 | (avl-tree--del-balance node branch 1)) | |
198 | (setf (avl-tree--node-data q) (avl-tree--node-data br) | |
199 | (avl-tree--node-branch node branch) | |
200 | (avl-tree--node-left br)) | |
b74e26bb | 201 | t))) |
1e38b8ff | 202 | |
afdd184c | 203 | (defun avl-tree--do-delete (cmpfun root branch data) |
1e38b8ff | 204 | ;; Return t if the height of the tree has shrunk. |
afdd184c | 205 | (let ((br (avl-tree--node-branch root branch))) |
1e38b8ff TTN |
206 | (cond |
207 | ((null br) | |
208 | nil) | |
209 | ||
afdd184c SM |
210 | ((funcall cmpfun data (avl-tree--node-data br)) |
211 | (if (avl-tree--do-delete cmpfun br 0 data) | |
3769ddcf | 212 | (avl-tree--del-balance root branch 0))) |
1e38b8ff | 213 | |
afdd184c SM |
214 | ((funcall cmpfun (avl-tree--node-data br) data) |
215 | (if (avl-tree--do-delete cmpfun br 1 data) | |
3769ddcf | 216 | (avl-tree--del-balance root branch 1))) |
1e38b8ff TTN |
217 | |
218 | (t | |
219 | ;; Found it. Let's delete it. | |
220 | (cond | |
afdd184c | 221 | ((null (avl-tree--node-right br)) |
3769ddcf TC |
222 | (setf (avl-tree--node-branch root branch) (avl-tree--node-left br)) |
223 | t) | |
1e38b8ff | 224 | |
afdd184c | 225 | ((null (avl-tree--node-left br)) |
3769ddcf TC |
226 | (setf (avl-tree--node-branch root branch) |
227 | (avl-tree--node-right br)) | |
228 | t) | |
1e38b8ff TTN |
229 | |
230 | (t | |
3769ddcf TC |
231 | (if (avl-tree--do-del-internal br 0 br) |
232 | (avl-tree--del-balance root branch 0)))))))) | |
1e38b8ff TTN |
233 | |
234 | ;; ---------------------------------------------------------------- | |
235 | ;; Entering data | |
236 | ||
3769ddcf TC |
237 | (defun avl-tree--enter-balance (node branch dir) |
238 | "Rebalance tree after an insertion | |
239 | into the left (DIR=0) or right (DIR=1) sub-tree of the | |
240 | left (BRANCH=0) or right (BRANCH=1) child of NODE. | |
241 | Return t if the height of the tree has grown." | |
afdd184c | 242 | (let ((br (avl-tree--node-branch node branch)) |
3769ddcf TC |
243 | ;; opposite direction: 0,1 -> 1,0 |
244 | (opp (avl-tree--switch-dir dir)) | |
245 | ;; direction 0,1 -> sign factor -1,+1 | |
246 | (sgn (avl-tree--dir-to-sign dir)) | |
8fa13442 | 247 | p1 p2 b2 result) |
1e38b8ff | 248 | (cond |
3769ddcf | 249 | ((< (* sgn (avl-tree--node-balance br)) 0) |
afdd184c | 250 | (setf (avl-tree--node-balance br) 0) |
1e38b8ff TTN |
251 | nil) |
252 | ||
afdd184c | 253 | ((= (avl-tree--node-balance br) 0) |
3769ddcf | 254 | (setf (avl-tree--node-balance br) sgn) |
1e38b8ff TTN |
255 | t) |
256 | ||
257 | (t | |
b74e26bb | 258 | ;; Tree has grown => Rebalance. |
3769ddcf TC |
259 | (setq p1 (avl-tree--node-branch br dir)) |
260 | (if (> (* sgn (avl-tree--node-balance p1)) 0) | |
261 | ;; Single rotation. | |
b74e26bb | 262 | (progn |
3769ddcf TC |
263 | (setf (avl-tree--node-branch br dir) |
264 | (avl-tree--node-branch p1 opp)) | |
265 | (setf (avl-tree--node-branch p1 opp) br) | |
afdd184c SM |
266 | (setf (avl-tree--node-balance br) 0) |
267 | (setf (avl-tree--node-branch node branch) p1)) | |
b74e26bb | 268 | |
3769ddcf TC |
269 | ;; Double rotation. |
270 | (setf p2 (avl-tree--node-branch p1 opp) | |
271 | b2 (avl-tree--node-balance p2) | |
272 | (avl-tree--node-branch p1 opp) | |
273 | (avl-tree--node-branch p2 dir) | |
274 | (avl-tree--node-branch p2 dir) p1 | |
275 | (avl-tree--node-branch br dir) | |
276 | (avl-tree--node-branch p2 opp) | |
277 | (avl-tree--node-branch p2 opp) br | |
278 | (avl-tree--node-balance br) | |
279 | (if (> (* sgn b2) 0) (- sgn) 0) | |
280 | (avl-tree--node-balance p1) | |
281 | (if (< (* sgn b2) 0) sgn 0) | |
282 | (avl-tree--node-branch node branch) p2 | |
283 | (avl-tree--node-balance | |
284 | (avl-tree--node-branch node branch)) 0)) | |
b74e26bb | 285 | nil)))) |
1e38b8ff | 286 | |
afdd184c | 287 | (defun avl-tree--do-enter (cmpfun root branch data) |
1e38b8ff | 288 | ;; Return t if height of tree ROOT has grown. INTERNAL USE ONLY. |
afdd184c | 289 | (let ((br (avl-tree--node-branch root branch))) |
1e38b8ff TTN |
290 | (cond |
291 | ((null br) | |
b74e26bb | 292 | ;; Data not in tree, insert it. |
afdd184c SM |
293 | (setf (avl-tree--node-branch root branch) |
294 | (avl-tree--node-create nil nil data 0)) | |
1e38b8ff TTN |
295 | t) |
296 | ||
afdd184c SM |
297 | ((funcall cmpfun data (avl-tree--node-data br)) |
298 | (and (avl-tree--do-enter cmpfun br 0 data) | |
3769ddcf | 299 | (avl-tree--enter-balance root branch 0))) |
1e38b8ff | 300 | |
afdd184c SM |
301 | ((funcall cmpfun (avl-tree--node-data br) data) |
302 | (and (avl-tree--do-enter cmpfun br 1 data) | |
3769ddcf | 303 | (avl-tree--enter-balance root branch 1))) |
1e38b8ff TTN |
304 | |
305 | (t | |
afdd184c | 306 | (setf (avl-tree--node-data br) data) |
1e38b8ff TTN |
307 | nil)))) |
308 | ||
1e38b8ff TTN |
309 | ;; ---------------------------------------------------------------- |
310 | ||
3769ddcf TC |
311 | |
312 | ;;; INTERNAL USE ONLY | |
313 | (defun avl-tree--mapc (map-function root dir) | |
314 | "Apply MAP-FUNCTION to all nodes in the tree starting with ROOT. | |
315 | The function is applied in-order, either ascending (DIR=0) or | |
316 | descending (DIR=1). | |
317 | ||
318 | Note: MAP-FUNCTION is applied to the node and not to the data | |
319 | itself." | |
1e38b8ff | 320 | (let ((node root) |
25e32569 | 321 | (stack nil) |
3769ddcf | 322 | (go-dir t)) |
25e32569 | 323 | (push nil stack) |
1e38b8ff | 324 | (while node |
3769ddcf TC |
325 | (if (and go-dir |
326 | (avl-tree--node-branch node dir)) | |
327 | ;; Do the DIR subtree first. | |
b74e26bb | 328 | (progn |
25e32569 | 329 | (push node stack) |
3769ddcf | 330 | (setq node (avl-tree--node-branch node dir))) |
b74e26bb TTN |
331 | ;; Apply the function... |
332 | (funcall map-function node) | |
3769ddcf TC |
333 | ;; and do the opposite subtree. |
334 | (setq node (if (setq go-dir (avl-tree--node-branch | |
335 | node (avl-tree--switch-dir dir))) | |
336 | (avl-tree--node-branch | |
337 | node (avl-tree--switch-dir dir)) | |
afdd184c | 338 | (pop stack))))))) |
1e38b8ff | 339 | |
3769ddcf | 340 | ;;; INTERNAL USE ONLY |
afdd184c | 341 | (defun avl-tree--do-copy (root) |
3769ddcf | 342 | "Copy the avl tree with ROOT as root. Highly recursive." |
1e38b8ff TTN |
343 | (if (null root) |
344 | nil | |
afdd184c SM |
345 | (avl-tree--node-create |
346 | (avl-tree--do-copy (avl-tree--node-left root)) | |
347 | (avl-tree--do-copy (avl-tree--node-right root)) | |
348 | (avl-tree--node-data root) | |
349 | (avl-tree--node-balance root)))) | |
1e38b8ff | 350 | |
3769ddcf | 351 | |
afdd184c SM |
352 | ;; ================================================================ |
353 | ;;; The public functions which operate on AVL trees. | |
1e38b8ff | 354 | |
3769ddcf TC |
355 | ;; define public alias for constructors so that we can set docstring |
356 | (defalias 'avl-tree-create 'avl-tree--create | |
357 | "Create an empty avl tree. | |
358 | COMPARE-FUNCTION is a function which takes two arguments, A and B, | |
359 | and returns non-nil if A is less than B, and nil otherwise.") | |
360 | ||
afdd184c SM |
361 | (defalias 'avl-tree-compare-function 'avl-tree--cmpfun |
362 | "Return the comparison function for the avl tree TREE. | |
1e38b8ff | 363 | |
afdd184c | 364 | \(fn TREE)") |
1e38b8ff | 365 | |
85718043 | 366 | (defun avl-tree-empty (tree) |
d385b030 | 367 | "Return t if avl tree TREE is emtpy, otherwise return nil." |
afdd184c | 368 | (null (avl-tree--root tree))) |
1e38b8ff | 369 | |
85718043 | 370 | (defun avl-tree-enter (tree data) |
1e38b8ff TTN |
371 | "In the avl tree TREE insert DATA. |
372 | Return DATA." | |
afdd184c | 373 | (avl-tree--do-enter (avl-tree--cmpfun tree) |
3769ddcf TC |
374 | (avl-tree--dummyroot tree) |
375 | 0 | |
376 | data) | |
1e38b8ff TTN |
377 | data) |
378 | ||
85718043 | 379 | (defun avl-tree-delete (tree data) |
1e38b8ff | 380 | "From the avl tree TREE, delete DATA. |
d385b030 TTN |
381 | Return the element in TREE which matched DATA, |
382 | nil if no element matched." | |
afdd184c SM |
383 | (avl-tree--do-delete (avl-tree--cmpfun tree) |
384 | (avl-tree--dummyroot tree) | |
385 | 0 | |
386 | data)) | |
1e38b8ff | 387 | |
85718043 | 388 | (defun avl-tree-member (tree data) |
1e38b8ff | 389 | "Return the element in the avl tree TREE which matches DATA. |
d385b030 TTN |
390 | Matching uses the compare function previously specified in |
391 | `avl-tree-create' when TREE was created. | |
1e38b8ff TTN |
392 | |
393 | If there is no such element in the tree, the value is nil." | |
afdd184c | 394 | (let ((node (avl-tree--root tree)) |
3769ddcf TC |
395 | (compare-function (avl-tree--cmpfun tree))) |
396 | (catch 'found | |
397 | (while node | |
398 | (cond | |
399 | ((funcall compare-function data (avl-tree--node-data node)) | |
400 | (setq node (avl-tree--node-left node))) | |
401 | ((funcall compare-function (avl-tree--node-data node) data) | |
402 | (setq node (avl-tree--node-right node))) | |
403 | (t (throw 'found (avl-tree--node-data node))))) | |
1e38b8ff TTN |
404 | nil))) |
405 | ||
3769ddcf TC |
406 | (defun avl-tree-map (__map-function__ tree &optional reverse) |
407 | "Modify all elements in the avl tree TREE by applying FUNCTION. | |
408 | ||
409 | Each element is replaced by the return value of FUNCTION applied | |
410 | to that element. | |
411 | ||
412 | FUNCTION is applied to the elements in ascending order, or | |
413 | descending order if REVERSE is non-nil." | |
afdd184c SM |
414 | (avl-tree--mapc |
415 | (lambda (node) | |
416 | (setf (avl-tree--node-data node) | |
417 | (funcall __map-function__ (avl-tree--node-data node)))) | |
3769ddcf TC |
418 | (avl-tree--root tree) |
419 | (if reverse 1 0))) | |
1e38b8ff | 420 | |
85718043 | 421 | (defun avl-tree-first (tree) |
1e38b8ff | 422 | "Return the first element in TREE, or nil if TREE is empty." |
afdd184c SM |
423 | (let ((node (avl-tree--root tree))) |
424 | (when node | |
425 | (while (avl-tree--node-left node) | |
426 | (setq node (avl-tree--node-left node))) | |
427 | (avl-tree--node-data node)))) | |
1e38b8ff | 428 | |
85718043 | 429 | (defun avl-tree-last (tree) |
1e38b8ff | 430 | "Return the last element in TREE, or nil if TREE is empty." |
afdd184c SM |
431 | (let ((node (avl-tree--root tree))) |
432 | (when node | |
433 | (while (avl-tree--node-right node) | |
434 | (setq node (avl-tree--node-right node))) | |
435 | (avl-tree--node-data node)))) | |
1e38b8ff | 436 | |
85718043 | 437 | (defun avl-tree-copy (tree) |
1e38b8ff | 438 | "Return a copy of the avl tree TREE." |
afdd184c SM |
439 | (let ((new-tree (avl-tree-create (avl-tree--cmpfun tree)))) |
440 | (setf (avl-tree--root new-tree) (avl-tree--do-copy (avl-tree--root tree))) | |
1e38b8ff TTN |
441 | new-tree)) |
442 | ||
85718043 | 443 | (defun avl-tree-flatten (tree) |
1e38b8ff | 444 | "Return a sorted list containing all elements of TREE." |
1e38b8ff | 445 | (let ((treelist nil)) |
afdd184c SM |
446 | (avl-tree--mapc |
447 | (lambda (node) (push (avl-tree--node-data node) treelist)) | |
3769ddcf TC |
448 | (avl-tree--root tree) 1) |
449 | treelist)) | |
1e38b8ff | 450 | |
85718043 | 451 | (defun avl-tree-size (tree) |
1e38b8ff TTN |
452 | "Return the number of elements in TREE." |
453 | (let ((treesize 0)) | |
afdd184c SM |
454 | (avl-tree--mapc |
455 | (lambda (data) (setq treesize (1+ treesize))) | |
3769ddcf | 456 | (avl-tree--root tree) 0) |
1e38b8ff TTN |
457 | treesize)) |
458 | ||
85718043 | 459 | (defun avl-tree-clear (tree) |
1e38b8ff | 460 | "Clear the avl tree TREE." |
afdd184c | 461 | (setf (avl-tree--root tree) nil)) |
1e38b8ff | 462 | |
fb5da2db TTN |
463 | (provide 'avl-tree) |
464 | ||
85718043 | 465 | ;;; avl-tree.el ends here |