Removing multiple nodes from the binary search tree.

Question

I have a binary search tree created in C. The problem is that I cannot find an effective way to delete all nodes, for example id> 5.

When I cross the tree, if I remove the node, the recursion gets an error because the structure is not the same.

Is there any way instead of using an auxiliary stack to store data before deleting it from the tree?

Answer 1

Have you tried to leave an order?
Remove the node after your children.

Answer 2

Costas. You need to provide additional information.

A binary tree simply means a tree whose nodes (maximum) have two children. On such a tree, you can arrange many ways:

• Unordered: There is no relationship between the parent and its nodes.
• Heap: A node has more (or less) all of its children
• Ordered: one child is indicated by a smaller one, and the other by a larger one. All values ​​smaller than the root are on one side, all values ​​are larger than others.

If you give us the code, we can help more.

Answer 3

I would prefer the AVL tree for this saturation.

here is the code you want

class BSTree { /* */ public static final int INSERT = 1; /* */ public static final int DELETE = -1; /* */ BTNode root; /* */ boolean AVL; /* */ boolean SPL; /* */ boolean RBL; /* */ BTNode lastnode; /* */ int nextside; /* */ /* */ public BSTree(int mode) /* */ { /* 18 */ this.root = null; /* 19 */ setMode(mode, true); /* */ } /* */ /* */ public void setMode(int mode, boolean state) { /* 23 */ switch (mode) /* */ { /* */ case 1: /* 26 */ if (state == true) /* */ { /* 28 */ this.AVL = true; /* 29 */ this.SPL = false; /* 30 */ this.RBL = false; /* */ /* 26 */ return; /* */ } /* */ /* 33 */ this.AVL = false; /* 34 */ break; /* */ case 2: /* 37 */ if (state == true) /* */ { /* 39 */ this.SPL = true; /* 40 */ this.AVL = false; /* 41 */ this.RBL = false; /* */ /* 37 */ return; /* */ } /* */ /* 44 */ this.SPL = false; /* 45 */ break; /* */ case 3: /* 48 */ if (state == true) /* */ { /* 50 */ this.RBL = true; /* 51 */ this.AVL = false; /* 52 */ this.SPL = false; /* */ /* 48 */ return; /* */ } /* */ /* 55 */ this.RBL = false; /* 56 */ break; /* */ default: /* 59 */ this.AVL = false; /* 60 */ this.SPL = false; /* 61 */ this.RBL = false; /* */ } /* */ } /* */ /* */ public boolean isAVL() { /* 66 */ return this.AVL; /* */ } /* */ /* */ public boolean isSPL() { /* 70 */ return this.SPL; /* */ } /* */ /* */ public boolean isRBL() { /* 74 */ return this.RBL; /* */ } /* */ /* */ public BTNode getRoot() /* */ { /* 79 */ return this.root; /* */ } /* */ /* */ public void setRoot(BTNode node) { /* 83 */ this.root = node; /* */ } /* */ /* */ public boolean isEmpty() { /* 87 */ return (this.root == null); /* */ } /* */ /* */ public int getDepth() /* */ { /* 92 */ int maxdepth = 0; /* 93 */ for (BTNode node = this.root; node != null; node = node.nextPrO()) /* */ { /* 95 */ int depth = node.getDepth(this.root); /* 96 */ if (depth > maxdepth) /* 97 */ maxdepth = depth; /* */ } /* 99 */ return maxdepth; /* */ } /* */ /* */ public void destroy(BTNode node) /* */ { /* 104 */ node = null; /* */ } /* */ /* */ public BTNode find(BTData data) /* */ { /* 113 */ BTNode node = locate(data); /* 114 */ if (isSPL()) /* 115 */ splay(this.lastnode); /* 116 */ return node; /* */ } /* */ /* */ public BTNode insert(BTData data) { /* 120 */ if (isSPL()) { /* 121 */ return insertSPL(data); /* */ } /* 123 */ if (isAVL()) { /* 124 */ return insertAVL(data); /* */ } /* 126 */ if (isRBL()) { /* 127 */ return insertRBL(data); /* */ } /* 129 */ return insertBST(data); /* */ } /* */ /* */ public BTNode delete(BTData data, int minmax) { /* 133 */ if (isAVL()) { /* 134 */ return deleteAVL(data, minmax); /* */ } /* 136 */ if (isSPL()) { /* 137 */ return deleteSPL(data, minmax); /* */ } /* 139 */ if (isRBL()) { /* 140 */ return deleteRBL(data, minmax); /* */ } /* 142 */ return deleteBST(data, minmax); /* */ } /* */ /* */ public BTNode locate(BTData data) /* */ { /* 150 */ BTNode node = this.root; /* 151 */ BTNode next = null; /* 152 */ int side = 0; /* */ /* 154 */ while (node != null) /* */ { /* 156 */ side = node.compareSide(data); /* 157 */ next = node.getChild(side); /* 158 */ if (next == node) break; if (next == null) /* */ break; /* 160 */ node = next; /* */ } /* 162 */ this.lastnode = node; /* 163 */ this.nextside = side; /* 164 */ return next; /* */ } /* */ /* */ public BTNode add(BTNode node, int side, BTData data) /* */ { /* 170 */ BTNode newnode = new BTNode(data); /* 171 */ link(node, side, newnode); /* 172 */ return newnode; /* */ } /* */ /* */ public BTNode remove(BTNode node) /* */ { /* 181 */ BTNode child = node.getChild(); /* 182 */ BTNode parent = node.getParent(); /* 183 */ int side = node.getSide(); /* 184 */ link(parent, side, child); /* 185 */ destroy(node); /* 186 */ return parent; /* */ } /* */ /* */ public void link(BTNode parent, int side, BTNode child) /* */ { /* 193 */ if (child != null) /* 194 */ child.setParent(parent); /* 195 */ if (parent != null) /* 196 */ parent.setChild(side, child); /* */ else /* 198 */ this.root = child; /* */ } /* */ /* */ public BTNode rotate(BTNode node, int side) /* */ { /* 206 */ BTNode parent = node.getParent(); /* 207 */ BTNode child = node.getChild(-side); /* 208 */ BTNode grand = child.getChild(side); /* */ /* 210 */ link(node, -side, grand); /* 211 */ link(parent, node.getSide(), child); /* 212 */ link(child, side, node); /* 213 */ return child; /* */ } /* */ /* */ public BTNode swap(BTNode node, int minmax) /* */ { /* 222 */ BTNode swap = getSuccessor(node, minmax); /* 223 */ BTNode temp = node; /* 224 */ swapData(node, swap); /* 225 */ node = swap; /* 226 */ swap = temp; /* 227 */ return node; /* */ } /* */ /* */ public BTNode getSuccessor(BTNode node, int minmax) { /* 231 */ return ((minmax == 1) ? node.prevInO() : node.nextInO()); /* */ } /* */ /* */ public void swapData(BTNode node1, BTNode node2) /* */ { /* 237 */ BTData data = node1.getData(); /* 238 */ node1.setData(node2.getData()); /* 239 */ node2.setData(data); /* */ } /* */ /* */ public void deleteAll() /* */ { /* 245 */ for (BTNode node = this.root.firstPoO(); node != null; ) /* */ { /* 247 */ BTNode leaf = node; /* 248 */ node = leaf.nextPoO(); /* 249 */ destroy(leaf); /* */ } /* 251 */ this.root = null; /* */ } /* */ /* */ public BTNode locateBST(BTData data) /* */ { /* 260 */ for (BTNode node = this.root; node != null; ) /* */ { /* 262 */ int side = node.compareSide(data); /* 263 */ if (side == 0) /* */ break; /* 265 */ node = node.getChild(side); /* */ } /* 267 */ return node; /* */ } /* */ /* */ public BTNode insertBST(BTData data) /* */ { /* 272 */ if (this.root == null) /* 273 */ return add(null, 0, data); /* 274 */ BTNode node = locate(data); /* 275 */ return ((node != null) ? null : add(this.lastnode, this.nextside, data)); /* */ } /* */ /* */ public BTNode deleteBST(BTData data, int minmax) /* */ { /* 280 */ BTNode node = locate(data); /* 281 */ if (node == null) /* 282 */ return null; /* 283 */ if (node.hasTwoChildren()) /* 284 */ node = swap(node, minmax); /* 285 */ return remove(node); /* */ } /* */ /* */ public BTNode insertAVL(BTData data) /* */ { /* 297 */ if (this.root == null) /* 298 */ return add(null, 0, data); /* 299 */ if (locate(data) != null) /* 300 */ return null; /* 301 */ BTNode node = add(this.lastnode, this.nextside, data); /* 302 */ rebalanceAVL(this.lastnode, this.nextside, 1); /* 303 */ return node; /* */ } /* */ /* */ public BTNode deleteAVL(BTData data, int minmax) /* */ { /* 315 */ BTNode node = locate(data); /* 316 */ if (node == null) { /* 317 */ return null; /* */ } /* 319 */ if (node.hasTwoChildren()) { /* 320 */ node = swap(node, minmax); /* */ } /* 322 */ int side = node.getSide(); /* 323 */ node = remove(node); /* 324 */ rebalanceAVL(node, side, -1); /* 325 */ return node; /* */ } /* */ /* */ public void rebalanceAVL(BTNode node, int side, int in) /* */ { /* 333 */ for (; node != null; node = node.getParent()) /* */ { /* 335 */ if (node.getBalance() != in * side) /* 336 */ node.setBalance(node.getBalance() + in * side); /* */ else { /* 338 */ node = rotateAVL(node); /* */ } /* 340 */ if ((in == 1) && (node.getBalance() == 0)) return; if ((in == -1) && (node.getBalance() != 0)) /* */ return; /* 342 */ side = node.getSide(); /* */ } /* */ } /* */ /* */ public BTNode rotateAVL(BTNode node) /* */ { /* 357 */ int side = node.getBalance(); /* 358 */ BTNode child = node.getChild(side); /* */ /* 360 */ if (child.getBalance() == -side) /* */ { /* 362 */ BTNode grand = child.getChild(-side); /* 363 */ if (grand.getBalance() == -side) /* */ { /* 365 */ grand.setBalance(0); /* 366 */ child.setBalance(side); /* 367 */ node.setBalance(0); /* */ } /* 369 */ else if (grand.getBalance() == side) /* */ { /* 371 */ grand.setBalance(0); /* 372 */ child.setBalance(0); /* 373 */ node.setBalance(-side); /* */ } /* */ else { /* 376 */ node.setBalance(0); /* 377 */ child.setBalance(0); /* */ } /* 379 */ rotate(child, side); /* */ } /* 382 */ else if (child.getBalance() == side) /* */ { /* 384 */ node.setBalance(0); /* 385 */ child.setBalance(0); /* */ } /* 387 */ else if (child.getBalance() == 0) /* */ { /* 389 */ node.setBalance(side); /* 390 */ child.setBalance(-side); /* */ } /* 392 */ node = rotate(node, -side); /* 393 */ return node; /* */ } /* */ /* */ public void balanceAVL(BTNode node) /* */ { /* 400 */ int side = node.getBalance(); /* 401 */ BTNode child = node.getChild(side); /* 402 */ if (child.getBalance() == -side) /* */ { /* 404 */ BTNode grand = child.getChild(-side); /* 405 */ if (grand.getBalance() == -side) /* */ { /* 407 */ grand.setBalance(0); /* 408 */ child.setBalance(side); /* 409 */ node.setBalance(0); /* */ } /* 411 */ else if (grand.getBalance() == side) /* */ { /* 413 */ grand.setBalance(0); /* 414 */ child.setBalance(0); /* 415 */ node.setBalance(-side); /* */ } /* */ else { /* 418 */ node.setBalance(0); /* 419 */ child.setBalance(0); /* */ } /* */ /* */ } /* 423 */ else if (child.getBalance() == side) /* */ { /* 425 */ child.setBalance(0); /* 426 */ node.setBalance(0); /* */ } else { /* 428 */ if (child.getBalance() != 0) /* */ return; /* 430 */ child.setBalance(-side); /* */ } /* */ } /* */ /* */ public boolean isAVLcompliant(BTNode node) /* */ { /* 440 */ boolean balanced = true; /* */ /* 442 */ if (node == null) /* 443 */ return true; /* 444 */ int l = getHeight(node.getChild(-1), 0); /* 445 */ int r = getHeight(node.getChild(1), 0); /* 446 */ node.setBalance(r - l); /* 447 */ if ((r - l > 1) || (r - l < -1)) /* 448 */ balanced = false; /* 449 */ return ((balanced) && (isAVLcompliant(node.getChild(-1))) && (isAVLcompliant (node.getChild(1)))); /* */ } /* */ /* */ public int getHeight(BTNode node, int depth) /* */ { /* 454 */ if (node == null) /* 455 */ return 0; /* 456 */ if (node.isLeaf()) { /* 457 */ return (depth + 1); /* */ } /* */ /* 460 */ int lmax = getHeight(node.getChild(-1), depth + 1); /* 461 */ int rmax = getHeight(node.getChild(1), depth + 1); /* 462 */ return ((lmax > rmax) ? lmax : rmax); /* */ } /* */ /* */ public BTNode insertSPL(BTData data) /* */ { /* 474 */ if (this.root == null) /* 475 */ return add(null, 0, data); /* 476 */ BTNode node = locate(data); /* 477 */ splay(this.lastnode); /* 478 */ return ((node != null) ? null : splitinsert(data)); /* */ } /* */ /* */ public BTNode splitinsert(BTData data) /* */ { /* 483 */ BTNode node = new BTNode(data); /* 484 */ int side = -this.root.compareSide(data); /* 485 */ BTNode child = this.root.getChild(-side); /* */ /* 487 */ this.root.setChild(-side, null); /* 488 */ link(node, side, this.root); /* 489 */ link(node, -side, child); /* 490 */ this.root = node; /* 491 */ return this.root; /* */ } /* */ /* */ public BTNode deleteSPL(BTData data, int minmax) /* */ { /* 498 */ BTNode node = locate(data); /* 499 */ splay(this.lastnode); /* 500 */ if (node == null) /* 501 */ return null; /* 502 */ BTNode root = node; /* 503 */ node = getSuccessor(root, minmax); /* 504 */ if (node != null) /* 505 */ splay(node); /* 506 */ return remove(root); /* */ } /* */ /* */ public void splay(BTNode node) /* */ { /* 516 */ while (node != this.root) /* */ { /* 518 */ BTNode parent = node.getParent(); /* 519 */ BTNode grandparent = parent.getParent(); /* 520 */ int side = node.getSide(); /* 521 */ if (grandparent == null) { /* 522 */ rotate(parent, -side); /* */ } /* 524 */ else if (parent.getSide() == side) /* */ { /* 526 */ rotate(grandparent, -side); /* 527 */ rotate(parent, -side); /* */ } /* */ else { /* 530 */ if (parent.getSide() == side) /* */ continue; /* 532 */ rotate(parent, -side); /* 533 */ rotate(grandparent, side); /* */ } /* */ } /* */ } /* */ /* */ public boolean isSPLcompliant() /* */ { /* 541 */ return true; /* */ } /* */ /* */ public BTNode insertRBL(BTData data) /* */ { /* 552 */ if (this.root == null) /* */ { /* 554 */ this.root = add(null, 0, data); /* 555 */ this.root.setColor(2); /* 556 */ return this.root; /* */ } /* 558 */ if (locate(data) != null) /* 559 */ return null; /* 560 */ BTNode node = add(this.lastnode, this.nextside, data); /* 561 */ node.setColor(1); /* 562 */ fixRBinsert(node); /* 563 */ return node; /* */ } /* */ /* */ public void fixRBinsert(BTNode node) /* */ { /* 571 */ while (node != this.root) /* */ { /* 573 */ BTNode parent = node.getParent(); /* 574 */ if (parent.getColor() == 2) /* */ break; /* 576 */ BTNode grandparent = parent.getParent(); /* 577 */ int side = parent.getSide(); /* 578 */ BTNode uncle = grandparent.getChild(-side); /* 579 */ if ((uncle != null) && (uncle.getColor() == 1)) /* */ { /* 581 */ parent.setColor(2); /* 582 */ uncle.setColor(2); /* 583 */ grandparent.setColor(1); /* 584 */ node = grandparent; /* */ } /* 586 */ else if (node.getSide() == -side) /* */ { /* 588 */ rotate(parent, side); /* 589 */ node = parent; /* */ } else { /* 591 */ if (node.getSide() != side) /* */ continue; /* 593 */ parent.setColor(2); /* 594 */ grandparent.setColor(1); /* 595 */ rotate(grandparent, -side); /* */ } /* */ } /* 598 */ this.root.setColor(2); /* */ } /* */ /* */ public BTNode deleteRBL(BTData data, int minmax) /* */ { /* 606 */ BTNode node = locate(data); /* 607 */ if (node == null) { /* 608 */ return null; /* */ } /* 610 */ if (node.hasTwoChildren()) { /* 611 */ node = swap(node, minmax); /* */ } /* 613 */ int color = node.getColor(); /* 614 */ int side = node.getSide(); /* 615 */ node = remove(node); /* 616 */ if ((this.root != null) && (side == 0)) { /* 617 */ this.root.setColor(2); /* */ } /* 619 */ else if ((node != null) && (color == 2)) /* 620 */ fixRBdelete(node, side); /* 621 */ return node; /* */ } /* */ /* */ public void fixRBdelete(BTNode parent, int side) /* */ { /* 629 */ BTNode node = parent.getChild(side); /* 630 */ if ((node != null) && (node.getColor() == 1)) /* */ { /* 632 */ node.setColor(2); /* 633 */ return; /* */ } /* */ /* */ do /* */ { /* 638 */ if (node != null) /* */ { /* 640 */ parent = node.getParent(); /* 641 */ side = node.getSide(); /* */ } /* 643 */ BTNode sibling = parent.getChild(-side); /* 644 */ BTNode nephew = sibling.getChild(side); /* 645 */ BTNode niece = sibling.getChild(-side); /* */ /* 647 */ if (sibling.getColor() == 1) /* */ { /* 649 */ sibling.setColor(2); /* 650 */ parent.setColor(1); /* 651 */ rotate(parent, side); /* */ } /* 654 */ else if ((isBlack(nephew)) && (isBlack(niece))) /* */ { /* 656 */ sibling.setColor(1); /* 657 */ node = (node == null) ? parent : node.getParent(); /* */ } /* 660 */ else if ((isBlack(niece)) && (isRed(nephew))) /* */ { /* 662 */ sibling.setColor(1); /* 663 */ nephew.setColor(2); /* 664 */ rotate(sibling, -side); /* */ } /* */ else { /* 667 */ if (!(isRed(niece))) /* */ continue; /* 669 */ sibling.setColor(parent.getColor()); /* 670 */ parent.setColor(2) ; /* 671 */ niece.setColor(2); /* 672 */ rotate(parent, side); /* 673 */ node = this.root; /* */ } /* */ } /* 636 */ while ((node != this.root) && (isBlack(node))); /* */ /* 676 */ node.setColor(2); /* */ } /* */ /* */ public boolean isRed(BTNode node) /* */ { /* 681 */ return ((node != null) && (node.getColor() == 1)); /* */ } /* */ /* */ public boolean isBlack(BTNode node) { /* 685 */ return ((node == null) || (node.getColor() == 2)); /* */ } /* */ /* */ public boolean isRBLcompliant(BTNode node) /* */ { /* 690 */ return false; /* */ } /* */ } 

This is a complete implementation. Good luck.

Answer 4

Can you go to the node and associate its children with the parent of the node so that you don't break the tree? The idea is to

• find node
• keep a link to your children
• save link to parent
• associate parent with node children
• only then remove node (free)

As wikipedia explains best, you have to be careful and determine how many children he has. After that, it's pretty simple.

Answer 5

I would do a normal walk, this gives you a list of orders for all the items. Then create the tree again.

Or, if you need to do this often, maybe better