1583 行
44 KiB
JavaScript

// Copyright 2011 David Galles, University of San Francisco. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other materials
// provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those of the
// authors and should not be interpreted as representing official policies, either expressed
// or implied, of the University of San Francisco
var FIRST_PRINT_POS_X = 50;
var PRINT_VERTICAL_GAP = 20;
var PRINT_MAX = 990;
var PRINT_HORIZONTAL_GAP = 50;
var MIN_MAX_DEGREE = 3;
var MAX_MAX_DEGREE = 7;
var HEIGHT_DELTA = 50;
var NODE_SPACING = 15;
var STARTING_Y = 30;
var WIDTH_PER_ELEM = 40;
var NODE_HEIGHT = 25;
var MESSAGE_X = 5;
var MESSAGE_Y = 10;
var LINK_COLOR = "#007700";
var HIGHLIGHT_CIRCLE_COLOR = "#007700";
var FOREGROUND_COLOR = "#007700";
var BACKGROUND_COLOR = "#EEFFEE";
var PRINT_COLOR = FOREGROUND_COLOR;
function BTree(am, w, h)
{
this.init(am, w, h);
}
BTree.prototype = new Algorithm();
BTree.prototype.varructor = BTree;
BTree.superclass = Algorithm.prototype;
BTree.prototype.init = function(am, w, h)
{
BTree.superclass.init.call(this, am, w, h);
this.nextIndex = 0;
this.starting_x = w / 2;
this.preemptiveSplit = false
this.addControls();
this.max_keys = 2;
this.min_keys = 1;
this.split_index = 1;
this.max_degree = 3;
this.messageID = this.nextIndex++;
this.cmd("CreateLabel", this.messageID, "", MESSAGE_X, MESSAGE_Y, 0);
this.moveLabel1ID = this.nextIndex++;
this.moveLabel2ID = this.nextIndex++;
animationManager.StartNewAnimation(this.commands);
animationManager.skipForward();
animationManager.clearHistory();
this.commands = new Array();
this.first_print_pos_y = h - 3 * PRINT_VERTICAL_GAP;
this.xPosOfNextLabel = 100;
this.yPosOfNextLabel = 200;
}
BTree.prototype.addControls = function()
{
this.controls = [];
this.insertField = addControlToAlgorithmBar("Text", "");
this.insertField.onkeydown = this.returnSubmit(this.insertField, this.insertCallback.bind(this), 4);
this.controls.push(this.insertField);
this.insertButton = addControlToAlgorithmBar("Button", "添加");
this.insertButton.onclick = this.insertCallback.bind(this);
this.controls.push(this.insertButton);
this.deleteField = addControlToAlgorithmBar("Text", "");
this.deleteField.onkeydown = this.returnSubmit(this.deleteField, this.deleteCallback.bind(this), 4);
this.controls.push(this.deleteField);
this.deleteButton = addControlToAlgorithmBar("Button", "删除");
this.deleteButton.onclick = this.deleteCallback.bind(this);
this.controls.push(this.deleteButton);
this.findField = addControlToAlgorithmBar("Text", "");
this.findField.onkeydown = this.returnSubmit(this.findField, this.findCallback.bind(this), 4);
this.controls.push(this.findField);
this.findButton = addControlToAlgorithmBar("Button", "搜索");
this.findButton.onclick = this.findCallback.bind(this);
this.controls.push(this.findButton);
this.printButton = addControlToAlgorithmBar("Button", "打印");
this.printButton.onclick = this.printCallback.bind(this);
this.controls.push(this.printButton);
this.clearButton = addControlToAlgorithmBar("Button", "清空");
this.clearButton.onclick = this.clearCallback.bind(this);
this.controls.push(this.clearButton);
var i;
radioButtonNames = [];
for (i = MIN_MAX_DEGREE; i <= MAX_MAX_DEGREE; i++)
{
radioButtonNames.push(' ' + String(i) + ' 阶');
}
this.maxDegreeRadioButtons = addRadioButtonGroupToAlgorithmBar(radioButtonNames, "MaxDegree");
this.maxDegreeRadioButtons[0].checked = true;
for(i = 0; i < this.maxDegreeRadioButtons.length; i++)
{
this.maxDegreeRadioButtons[i].onclick = this.maxDegreeChangedHandler.bind(this,i+MIN_MAX_DEGREE);
}
this.premptiveSplitBox = addCheckboxToAlgorithmBar("Preemtive Split / Merge (Even max degree only)");
this.premptiveSplitBox.onclick = this.premtiveSplitCallback.bind(this);
// Other buttons ...
}
BTree.prototype.reset = function()
{
this.nextIndex = 3;
this.max_degree = 3;
this.max_keys = 2;
this.min_keys = 1;
this.split_index = 1;
// NOTE: The order of these last two this.commands matters!
this.treeRoot = null;
this.ignoreInputs = true;
// maxDegreeButtonArray[this.max_degree].selected = true;
this.ignoreInputs = false;
}
BTree.prototype.enableUI = function(event)
{
var i;
for (i = 0; i < this.controls.length; i++)
{
this.controls[i].disabled = false;
}
// TODO Only enable even maxdegree if preemptive merge is on
if (this.preemptiveSplit)
{
var initialEven = MIN_MAX_DEGREE % 2;
var i;
for (i = initialEven; i <= MAX_MAX_DEGREE - MIN_MAX_DEGREE; i+= 2)
{
this.maxDegreeRadioButtons[i].disabled = false;
}
}
else
{
for (i = 0; i < this.maxDegreeRadioButtons.length; i++)
{
this.maxDegreeRadioButtons[i].disabled = false;
}
}
if (this.max_degree % 2 == 0)
{
this.premptiveSplitBox.disabled = false;
}
}
BTree.prototype.disableUI = function(event)
{
for (var i = 0; i < this.controls.length; i++)
{
this.controls[i].disabled = true;
}
for (i = 0; i < this.maxDegreeRadioButtons.length; i++)
{
this.maxDegreeRadioButtons[i].disabled = true;
}
this.premptiveSplitBox.disabled = true;
}
//TODO: Fix me!
BTree.prototype.maxDegreeChangedHandler = function(newMaxDegree, event)
{
if (this.max_degree != newMaxDegree)
{
this.implementAction(this.changeDegree.bind(this), newMaxDegree);
animationManager.skipForward();
animationManager.clearHistory();
}
}
BTree.prototype.insertCallback = function(event)
{
var insertedValue;
insertedValue = this.normalizeNumber(this.insertField.value, 4);
if (insertedValue != "")
{
this.insertField.value = "";
this.implementAction(this.insertElement.bind(this),insertedValue);
}
}
BTree.prototype.deleteCallback = function(event)
{
var deletedValue = this.deleteField.value;
if (deletedValue != "")
{
deletedValue = this.normalizeNumber(this.deleteField.value, 4);
this.deleteField.value = "";
this.implementAction(this.deleteElement.bind(this),deletedValue);
}
}
BTree.prototype.clearCallback = function(event)
{
this.implementAction(this.clearTree.bind(this), "");
}
BTree.prototype.premtiveSplitCallback = function(event)
{
if (this.preemptiveSplit != this.premptiveSplitBox.checked)
{
this.implementAction(this.changePreemtiveSplit.bind(this), this.premptiveSplitBox.checked);
}
}
BTree.prototype.changePreemtiveSplit = function(newValue)
{
this.commands = new Array();
this.cmd("Step");
this.preemptiveSplit = newValue;
if (this.premptiveSplitBox.checked != this.preemptiveSplit)
{
this.premptiveSplitBox.checked = this.preemptiveSplit;
}
return this.commands;
}
BTree.prototype.printCallback = function(event)
{
this.implementAction(this.printTree.bind(this),"");
}
BTree.prototype.printTree = function(unused)
{
this.commands = new Array();
this.cmd("SetText", this.messageID, "Printing tree");
var firstLabel = this.nextIndex;
this.xPosOfNextLabel = FIRST_PRINT_POS_X;
this.yPosOfNextLabel = this.first_print_pos_y;
this.printTreeRec(this.treeRoot);
this.cmd("Step");
for (var i = firstLabel; i < this.nextIndex; i++)
{
this.cmd("Delete", i);
}
this.nextIndex = firstLabel;
this.cmd("SetText", this.messageID, "");
return this.commands;
}
BTree.prototype.printTreeRec =function (tree)
{
this.cmd("SetHighlight", tree.graphicID, 1);
var nextLabelID;
if (tree.isLeaf)
{
for (var i = 0; i < tree.numKeys;i++)
{
nextLabelID = this.nextIndex++;
this.cmd("CreateLabel", nextLabelID, tree.keys[i], this.getLabelX(tree, i), tree.y);
this.cmd("SetForegroundColor", nextLabelID, PRINT_COLOR);
this.cmd("Move", nextLabelID, this.xPosOfNextLabel, this.yPosOfNextLabel);
this.cmd("Step");
this.xPosOfNextLabel += PRINT_HORIZONTAL_GAP;
if (this.xPosOfNextLabel > PRINT_MAX)
{
this.xPosOfNextLabel = FIRST_PRINT_POS_X;
this.yPosOfNextLabel += PRINT_VERTICAL_GAP;
}
}
this.cmd("SetHighlight", tree.graphicID, 0);
}
else
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[0].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[0].graphicID, 0);
this.printTreeRec(tree.children[0]);
for (i = 0; i < tree.numKeys; i++)
{
this.cmd("SetHighlight", tree.graphicID, 1);
nextLabelID = this.nextIndex++;
this.cmd("CreateLabel", nextLabelID, tree.keys[i], this.getLabelX(tree, i), tree.y);
this.cmd("SetForegroundColor", nextLabelID, PRINT_COLOR);
this.cmd("Move", nextLabelID, this.xPosOfNextLabel, this.yPosOfNextLabel);
this.cmd("Step");
this.xPosOfNextLabel += PRINT_HORIZONTAL_GAP;
if (this.xPosOfNextLabel > PRINT_MAX)
{
this.xPosOfNextLabel = FIRST_PRINT_POS_X;
this.yPosOfNextLabel += PRINT_VERTICAL_GAP;
}
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 0);
this.printTreeRec(tree.children[i+1]);
}
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
}
}
BTree.prototype.clearTree = function(ignored)
{
this.commands = new Array();
this.deleteTree(this.treeRoot);
this.treeRoot = null;
this.nextIndex = 3;
return this.commands;
}
BTree.prototype.deleteTree = function(tree)
{
if (tree != null)
{
if (!tree.isLeaf)
{
for (var i = 0; i <= tree.numKeys; i++)
{
this.cmd("Disconnect", tree.graphicID, tree.children[i].graphicID);
this.deleteTree(tree.children[i]);
tree.children[i] == null;
}
}
this.cmd("Delete", tree.graphicID);
}
}
BTree.prototype.changeDegree = function(degree)
{
this.commands = new Array();
this.deleteTree(this.treeRoot);
this.treeRoot = null;
this.nextIndex = 3;
var newDegree = degree;
this.ignoreInputs = true;
//TODO: Check me!
this.maxDegreeRadioButtons[newDegree - MIN_MAX_DEGREE].checked = true;
this.ignoreInputs = false;
this.max_degree = newDegree;
this.max_keys = newDegree - 1;
this.min_keys = Math.floor((newDegree + 1) / 2) - 1;
this.split_index = Math.floor((newDegree - 1) / 2);
if (this.commands.length == 0)
{
this.cmd("Step");
}
if (newDegree % 2 != 0 && this.preemptiveSplit)
{
this.preemptiveSplit = false;
this.premptiveSplitBox.checked = false;
}
return this.commands;
}
BTree.prototype.findCallback = function(event)
{
var findValue;
findValue = this.normalizeNumber(this.findField.value, 4);
this.findField.value = "";
this.implementAction(this.findElement.bind(this),findValue);
}
BTree.prototype.findElement = function(findValue)
{
this.commands = new Array();
this.cmd("SetText", this.messageID, "Finding " + findValue);
this.findInTree(this.treeRoot, findValue);
return this.commands;
}
BTree.prototype.findInTree = function(tree, val)
{
if (tree != null)
{
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
var i;
for (i = 0; i < tree.numKeys && tree.keys[i] < val; i++);
if (i == tree.numKeys)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 0);
this.findInTree(tree.children[tree.numKeys], val);
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree");
}
}
else if (tree.keys[i] > val)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0);
this.findInTree(tree.children[i], val);
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree");
}
}
else
{
this.cmd("SetTextColor", tree.graphicID, "#FF0000", i);
this.cmd("SetText", this.messageID, "Element " + val + " found");
this.cmd("Step");
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("Step");
}
}
else
{
this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree");
}
}
BTree.prototype.insertElement = function(insertedValue)
{
this.commands = new Array();
this.cmd("SetText", this.messageID, "Inserting " + insertedValue);
this.cmd("Step");
if (this.treeRoot == null)
{
this.treeRoot = new BTreeNode(this.nextIndex++, this.starting_x, STARTING_Y);
this.cmd("CreateBTreeNode",
this.treeRoot.graphicID,
WIDTH_PER_ELEM, NODE_HEIGHT,
1,
this.starting_x,
STARTING_Y,
BACKGROUND_COLOR,
FOREGROUND_COLOR);
this.treeRoot.keys[0] = insertedValue;
this.cmd("SetText", this.treeRoot.graphicID, insertedValue, 0);
}
else
{
if (this.preemptiveSplit)
{
if (this.treeRoot.numKeys == this.max_keys)
{
this.split(this.treeRoot)
this.resizeTree();
this.cmd("Step");
}
this.insertNotFull(this.treeRoot, insertedValue);
}
else
{
this.insert(this.treeRoot, insertedValue);
}
if (!this.treeRoot.isLeaf)
{
this.resizeTree();
}
}
this.cmd("SetText", this.messageID, "");
return this.commands;
}
BTree.prototype.insertNotFull = function(tree, insertValue)
{
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
if (tree.isLeaf)
{
this.cmd("SetText", this.messageID, "Inserting " + insertValue + ". Inserting into a leaf");
tree.numKeys++;
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
var insertIndex = tree.numKeys - 1;
while (insertIndex > 0 && tree.keys[insertIndex - 1] > insertValue)
{
tree.keys[insertIndex] = tree.keys[insertIndex - 1];
this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex);
insertIndex--;
}
tree.keys[insertIndex] = insertValue;
this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex);
this.cmd("SetHighlight", tree.graphicID, 0);
this.resizeTree();
}
else
{
var findIndex = 0;
while (findIndex < tree.numKeys && tree.keys[findIndex] < insertValue)
{
findIndex++;
}
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 1);
this.cmd("Step");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 0);
this.cmd("SetHighlight", tree.graphicID, 0);
if (tree.children[findIndex].numKeys == this.max_keys)
{
var newTree = this.split(tree.children[findIndex]);
this.resizeTree();
this.cmd("Step");
this.insertNotFull(newTree, insertValue);
}
else
{
this.insertNotFull(tree.children[findIndex], insertValue);
}
}
}
BTree.prototype.insert = function(tree, insertValue)
{
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
if (tree.isLeaf)
{
this.cmd("SetText", this.messageID, "Inserting " + insertValue + ". Inserting into a leaf");
tree.numKeys++;
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
var insertIndex = tree.numKeys - 1;
while (insertIndex > 0 && tree.keys[insertIndex - 1] > insertValue)
{
tree.keys[insertIndex] = tree.keys[insertIndex - 1];
this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex);
insertIndex--;
}
tree.keys[insertIndex] = insertValue;
this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex);
this.cmd("SetHighlight", tree.graphicID, 0);
this.resizeTree();
this.insertRepair(tree);
}
else
{
var findIndex = 0;
while (findIndex < tree.numKeys && tree.keys[findIndex] < insertValue)
{
findIndex++;
}
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 1);
this.cmd("Step");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 0);
this.cmd("SetHighlight", tree.graphicID, 0);
this.insert(tree.children[findIndex], insertValue);
}
}
BTree.prototype.insertRepair = function(tree)
{
if (tree.numKeys <= this.max_keys)
{
return;
}
else if (tree.parent == null)
{
this.treeRoot = this.split(tree);
return;
}
else
{
var newNode = this.split(tree);
this.insertRepair(newNode);
}
}
BTree.prototype.split = function(tree)
{
this.cmd("SetText", this.messageID, "Node now contains too many keys. Splittig ...");
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
var rightNode = new BTreeNode(this.nextIndex++, tree.x + 100, tree.y);
rightNode.numKeys = tree.numKeys - this.split_index - 1;
var risingNode = tree.keys[this.split_index];
if (tree.parent != null)
{
var currentParent = tree.parent;
for (var parentIndex = 0; parentIndex < currentParent.numKeys + 1 && currentParent.children[parentIndex] != tree; parentIndex++);
if (parentIndex == currentParent.numKeys + 1)
{
throw new Error("Couldn't find which child we were!");
}
this.cmd("SetNumElements", currentParent.graphicID, currentParent.numKeys + 1);
for (i = currentParent.numKeys; i > parentIndex; i--)
{
currentParent.children[i+1] = currentParent.children[i];
this.cmd("Disconnect", currentParent.graphicID, currentParent.children[i].graphicID);
this.cmd("Connect", currentParent.graphicID, currentParent.children[i].graphicID, FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
i+1);
currentParent.keys[i] = currentParent.keys[i-1];
this.cmd("SetText", currentParent.graphicID, currentParent.keys[i] ,i);
}
currentParent.numKeys++;
currentParent.keys[parentIndex] = risingNode;
this.cmd("SetText", currentParent.graphicID, "", parentIndex);
this.moveLabel1ID = this.nextIndex++;
this.cmd("CreateLabel", this.moveLabel1ID, risingNode, this.getLabelX(tree, this.split_index), tree.y)
this.cmd("SetForegroundColor", this.moveLabel1ID, FOREGROUND_COLOR);
this.cmd("Move", this.moveLabel1ID, this.getLabelX(currentParent, parentIndex), currentParent.y)
currentParent.children[parentIndex+1] = rightNode;
rightNode.parent = currentParent;
}
this.cmd("CreateBTreeNode",
rightNode.graphicID,
WIDTH_PER_ELEM, NODE_HEIGHT,
tree.numKeys - this.split_index - 1,
tree.x,
tree.y,
BACKGROUND_COLOR,
FOREGROUND_COLOR);
var i;
for (i = this.split_index + 1; i < tree.numKeys + 1; i++)
{
rightNode.children[i - this.split_index - 1] = tree.children[i];
if (tree.children[i] != null)
{
rightNode.isLeaf = false;
this.cmd("Disconnect", tree.graphicID, tree.children[i].graphicID);
this.cmd("Connect", rightNode.graphicID,
rightNode.children[i - this.split_index - 1].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
i - this.split_index - 1);
if (tree.children[i] != null)
{
tree.children[i].parent = rightNode;
}
tree.children[i] = null;
}
}
for (i = this.split_index+1; i < tree.numKeys; i++)
{
rightNode.keys[i - this.split_index - 1] = tree.keys[i];
this.cmd("SetText", rightNode.graphicID, rightNode.keys[i - this.split_index - 1], i - this.split_index - 1);
}
var leftNode = tree;
leftNode.numKeys = this.split_index;
// TO MAKE UNDO WORK -- CAN REMOVE LATER VV
for (i = this.split_index; i < tree.numKeys; i++)
{
this.cmd("SetText", tree.graphicID, "", i);
}
// TO MAKE UNDO WORK -- CAN REMOVE LATER ^^
this.cmd("SetNumElements", tree.graphicID, this.split_index);
if (tree.parent != null)
{
this.cmd("Connect", currentParent.graphicID, rightNode.graphicID, FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
parentIndex + 1);
this.resizeTree();
this.cmd("Step")
this.cmd("Delete", this.moveLabel1ID);
this.cmd("SetText", currentParent.graphicID, risingNode, parentIndex);
return tree.parent;
}
else // if (tree.parent == null)
{
this.treeRoot = new BTreeNode(this.nextIndex++, this.starting_x, STARTING_Y);
this.cmd("CreateBTreeNode",
this.treeRoot.graphicID,
WIDTH_PER_ELEM,
NODE_HEIGHT,
1,
this.starting_x,
STARTING_Y,
BACKGROUND_COLOR,
FOREGROUND_COLOR);
this.treeRoot.keys[0] = risingNode;
this.cmd("SetText", this.treeRoot.graphicID, risingNode, 0);
this.treeRoot.children[0] = leftNode;
this.treeRoot.children[1] = rightNode;
leftNode.parent = this.treeRoot;
rightNode.parent = this.treeRoot;
this.cmd("Connect", this.treeRoot.graphicID, leftNode.graphicID, FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
0); // Connection Point
this.cmd("Connect", this.treeRoot.graphicID, rightNode.graphicID, FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
1); // Connection Point
this.treeRoot.isLeaf = false;
return this.treeRoot;
}
}
BTree.prototype.deleteElement = function(deletedValue)
{
this.commands = new Array();
this.cmd("SetText", 0, "正在刪除 "+deletedValue);
this.cmd("Step");
this.cmd("SetText", 0, "");
this.highlightID = this.nextIndex++;
this.cmd("SetText", 0, "");
if (this.preemptiveSplit)
{
this.doDeleteNotEmpty(this.treeRoot, deletedValue);
}
else
{
this.doDelete(this.treeRoot, deletedValue);
}
if (this.treeRoot.numKeys == 0)
{
this.cmd("Step");
this.cmd("Delete", this.treeRoot.graphicID);
this.treeRoot = this.treeRoot.children[0];
this.treeRoot.parent = null;
this.resizeTree();
}
return this.commands;
}
BTree.prototype.doDeleteNotEmpty = function(tree, val)
{
if (tree != null)
{
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
var i;
for (i = 0; i < tree.numKeys && tree.keys[i] < val; i++);
if (i == tree.numKeys)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 0);
if (tree.children[tree.numKeys].numKeys == this.min_keys)
{
var nextNode;
if (tree.children[tree.numKeys - 1].numKeys > this.min_keys)
{
nextNode = this.stealFromLeft(tree.children[tree.numKeys], tree.numKeys)
this.doDeleteNotEmpty(nextNode, val);
}
else
{
nextNode = this.mergeRight(tree.children[tree.numKeys - 1])
this.doDeleteNotEmpty(nextNode, val);
}
}
else
{
this.doDeleteNotEmpty(tree.children[tree.numKeys], val);
}
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
}
}
else if (tree.keys[i] > val)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0);
if (tree.children[i].numKeys > this.min_keys)
{
this.doDeleteNotEmpty(tree.children[i], val);
}
else
{
if (tree.children[i+1].numKeys > this.min_keys)
{
nextNode = this.stealFromRight(tree.children[i], i);
this.doDeleteNotEmpty(nextNode, val);
}
else
{
nextNode = this.mergeRight(tree.children[i]);
this.doDeleteNotEmpty(nextNode, val);
}
}
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
}
}
else
{
this.cmd("SetTextColor", tree.graphicID, "FF0000", i);
this.cmd("Step");
if (tree.isLeaf)
{
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
for (var j = i; j < tree.numKeys - 1; j++)
{
tree.keys[j] = tree.keys[j+1];
this.cmd("SetText", tree.graphicID, tree.keys[j], j);
}
tree.numKeys--;
this.cmd("SetText", tree.graphicID, "", tree.numKeys);
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
this.cmd("SetHighlight", tree.graphicID, 0);
this.resizeTree();
this.cmd("SetText", this.messageID, "");
}
else
{
this.cmd("SetText", this.messageID, "Checking to see if tree to left of element to delete \nhas an extra key");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1);
this.cmd("Step");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0);
var maxNode = tree.children[i];
if (tree.children[i].numKeys == this.min_keys)
{
this.cmd("SetText", this.messageID,
"Tree to left of element to delete does not have an extra key. \nLooking to the right ...");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 1);
this.cmd("Step");
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i + 1].graphicID, 0);
// Trees to left and right of node to delete don't have enough keys
// Do a merge, and then recursively delete the element
if (tree.children[i+1].numKeys == this.min_keys)
{
this.cmd("SetText", this.messageID,
"Neither subtree has extra nodes. Mergeing around the key to delete, \nand recursively deleting ...");
this.cmd("Step");
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
nextNode = this.mergeRight(tree.children[i]);
this.doDeleteNotEmpty(nextNode, val);
return;
}
else
{
this.cmd("SetText", this.messageID,
"Tree to right of element to delete does have an extra key. \nFinding the smallest key in that subtree ...");
this.cmd("Step");
var minNode = tree.children[i+1];
while (!minNode.isLeaf)
{
this.cmd("SetHighlight", minNode.graphicID, 1);
this.cmd("Step")
this.cmd("SetHighlight", minNode.graphicID, 0);
if (minNode.children[0].numKeys == this.min_keys)
{
if (minNode.children[1].numKeys == this.min_keys)
{
minNode = this.mergeRight(minNode.children[0]);
}
else
{
minNode = this.stealFromRight(minNode.children[0], 0);
}
}
else
{
minNode = minNode.children[0];
}
}
this.cmd("SetHighlight", minNode.graphicID, 1);
tree.keys[i] = minNode.keys[0];
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
this.cmd("SetText", tree.graphicID, "", i);
this.cmd("SetText", minNode.graphicID, "", 0);
this.cmd("CreateLabel", this.moveLabel1ID, minNode.keys[0], this.getLabelX(minNode, 0), minNode.y)
this.cmd("Move", this.moveLabel1ID, this.getLabelX(tree, i), tree.y);
this.cmd("Step");
this.cmd("Delete", this.moveLabel1ID);
this.cmd("SetText", tree.graphicID, tree.keys[i], i);
for (i = 1; i < minNode.numKeys; i++)
{
minNode.keys[i-1] = minNode.keys[i]
this.cmd("SetText", minNode.graphicID, minNode.keys[i-1], i - 1);
}
this.cmd("SetText", minNode.graphicID, "",minNode.numKeys - 1);
minNode.numKeys--;
this.cmd("SetHighlight", minNode.graphicID, 0);
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetNumElements", minNode.graphicID, minNode.numKeys);
this.resizeTree();
this.cmd("SetText", this.messageID, "");
}
}
else
{
this.cmd("SetText", this.messageID,
"Tree to left of element to delete does have \nan extra key. Finding the largest key in that subtree ...");
this.cmd("Step");
while (!maxNode.isLeaf)
{
this.cmd("SetHighlight", maxNode.graphicID, 1);
this.cmd("Step")
this.cmd("SetHighlight", maxNode.graphicID, 0);
if (maxNode.children[maxNode.numKeys].numKeys == this.min_keys)
{
if (maxNode.children[maxNode.numKeys - 1] > this.min_keys)
{
maxNode = this.stealFromLeft(maxNode.children[maxNode.numKeys], maxNode.numKeys);
}
else
{
} maxNode = this.mergeRight(maxNode.children[maxNode.numKeys-1]);
}
else
{
maxNode = maxNode.children[maxNode.numKeys];
}
}
this.cmd("SetHighlight", maxNode.graphicID, 1);
tree.keys[i] = maxNode.keys[maxNode.numKeys - 1];
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
this.cmd("SetText", tree.graphicID, "", i);
this.cmd("SetText", maxNode.graphicID, "", maxNode.numKeys - 1);
this.cmd("CreateLabel", this.moveLabel1ID, tree.keys[i], this.getLabelX(maxNode, maxNode.numKeys - 1), maxNode.y)
this.cmd("Move", this.moveLabel1ID, this.getLabelX(tree, i), tree.y);
this.cmd("Step");
this.cmd("Delete", this.moveLabel1ID);
this.cmd("SetText", tree.graphicID, tree.keys[i], i);
maxNode.numKeys--;
this.cmd("SetHighlight", maxNode.graphicID, 0);
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetNumElements", maxNode.graphicID, maxNode.numKeys);
this.resizeTree();
this.cmd("SetText", this.messageID, "");
}
}
}
}
}
BTree.prototype.doDelete = function(tree, val)
{
if (tree != null)
{
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("Step");
var i;
for (i = 0; i < tree.numKeys && tree.keys[i] < val; i++);
if (i == tree.numKeys)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 0);
this.doDelete(tree.children[tree.numKeys], val);
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
}
}
else if (tree.keys[i] > val)
{
if (!tree.isLeaf)
{
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1);
this.cmd("Step");
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0);
this.doDelete(tree.children[i], val);
}
else
{
this.cmd("SetHighlight", tree.graphicID, 0);
}
}
else
{
this.cmd("SetTextColor", tree.graphicID, "#FF0000", i);
this.cmd("Step");
if (tree.isLeaf)
{
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
for (var j = i; j < tree.numKeys - 1; j++)
{
tree.keys[j] = tree.keys[j+1];
this.cmd("SetText", tree.graphicID, tree.keys[j], j);
}
tree.numKeys--;
this.cmd("SetText", tree.graphicID, "", tree.numKeys);
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
this.cmd("SetHighlight", tree.graphicID, 0);
this.repairAfterDelete(tree);
}
else
{
var maxNode = tree.children[i];
while (!maxNode.isLeaf)
{
this.cmd("SetHighlight", maxNode.graphicID, 1);
this.cmd("Step")
this.cmd("SetHighlight", maxNode.graphicID, 0);
maxNode = maxNode.children[maxNode.numKeys];
}
this.cmd("SetHighlight", maxNode.graphicID, 1);
tree.keys[i] = maxNode.keys[maxNode.numKeys - 1];
this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i);
this.cmd("SetText", tree.graphicID, "", i);
this.cmd("SetText", maxNode.graphicID, "", maxNode.numKeys - 1);
this.cmd("CreateLabel", this.moveLabel1ID, tree.keys[i], this.getLabelX(maxNode, maxNode.numKeys - 1), maxNode.y)
this.cmd("Move", this.moveLabel1ID, this.getLabelX(tree, i), tree.y);
this.cmd("Step");
this.cmd("Delete", this.moveLabel1ID);
this.cmd("SetText", tree.graphicID, tree.keys[i], i);
maxNode.numKeys--;
this.cmd("SetHighlight", maxNode.graphicID, 0);
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetNumElements", maxNode.graphicID, maxNode.numKeys);
this.repairAfterDelete(maxNode);
}
}
}
}
BTree.prototype.mergeRight = function(tree)
{
this.cmd("SetText", this.messageID, "Merging node");
var parentNode = tree.parent;
var parentIndex = 0;
for (parentIndex = 0; parentNode.children[parentIndex] != tree; parentIndex++);
var rightSib = parentNode.children[parentIndex+1];
this.cmd("SetHighlight", tree.graphicID, 1);
this.cmd("SetHighlight", parentNode.graphicID, 1);
this.cmd("SetHighlight", rightSib.graphicID, 1);
this.cmd("Step");
this.cmd("SetNumElements", tree.graphicID, tree.numKeys + rightSib.numKeys + 1);
tree.x = (tree.x + rightSib.x) / 2
this.cmd("SetPosition", tree.graphicID, tree.x, tree.y);
tree.keys[tree.numKeys] = parentNode.keys[parentIndex];
var fromParentIndex = tree.numKeys;
//this.cmd("SetText", tree.graphicID, tree.keys[tree.numKeys], tree.numKeys);
this.cmd("SetText", tree.graphicID, "", tree.numKeys);
this.cmd("CreateLabel", this.moveLabel1ID, parentNode.keys[parentIndex], this.getLabelX(parentNode, parentIndex), parentNode.y);
for (var i = 0; i < rightSib.numKeys; i++)
{
tree.keys[tree.numKeys + 1 + i] = rightSib.keys[i];
this.cmd("SetText", tree.graphicID, tree.keys[tree.numKeys + 1 + i], tree.numKeys + 1 + i);
this.cmd("SetText", rightSib.graphicID, "", i);
}
if (!tree.isLeaf)
{
for (i = 0; i <= rightSib.numKeys; i++)
{
this.cmd("Disconnect", rightSib.graphicID, rightSib.children[i].graphicID);
tree.children[tree.numKeys + 1 + i] = rightSib.children[i];
tree.children[tree.numKeys + 1 + i].parent = tree;
this.cmd("Connect", tree.graphicID,
tree.children[tree.numKeys + 1 + i].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
tree.numKeys + 1 + i);
}
}
this.cmd("Disconnect", parentNode.graphicID, rightSib.graphicID);
for (i = parentIndex+1; i < parentNode.numKeys; i++)
{
this.cmd("Disconnect", parentNode.graphicID, parentNode.children[i+1].graphicID);
parentNode.children[i] = parentNode.children[i+1];
this.cmd("Connect", parentNode.graphicID,
parentNode.children[i].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
i);
parentNode.keys[i-1] = parentNode.keys[i];
this.cmd("SetText", parentNode.graphicID, parentNode.keys[i-1], i-1);
}
this.cmd("SetText", parentNode.graphicID, "", parentNode.numKeys - 1);
parentNode.numKeys--;
this.cmd("SetNumElements", parentNode.graphicID, parentNode.numKeys);
this.cmd("SetHighlight", tree.graphicID, 0);
this.cmd("SetHighlight", parentNode.graphicID, 0);
// this.cmd("SetHighlight", rightSib.graphicID, 0);
// this.cmd("Step");
this.cmd("Delete", rightSib.graphicID);
tree.numKeys = tree.numKeys + rightSib.numKeys + 1;
this.cmd("Move", this.moveLabel1ID, this.getLabelX(tree, fromParentIndex), tree.y);
this.cmd("Step");
// resizeTree();
this.cmd("Delete", this.moveLabel1ID);
this.cmd("SetText", tree.graphicID, tree.keys[fromParentIndex], fromParentIndex);
this.cmd("SetText", this.messageID, "");
return tree;
}
BTree.prototype.stealFromRight = function(tree, parentIndex)
{
// Steal from right sibling
var parentNode = tree.parent;
this.cmd("SetNumElements", tree.graphicID, tree.numKeys+1);
this.cmd("SetText", this.messageID, "Stealing from right sibling");
var rightSib = parentNode.children[parentIndex + 1];
tree.numKeys++;
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
this.cmd("SetText", tree.graphicID, "", tree.numKeys - 1);
this.cmd("SetText", parentNode.graphicID, "", parentIndex);
this.cmd("SetText", rightSib.graphicID, "", 0);
var tmpLabel1 = this.nextIndex++;
var tmpLabel2 = this.nextIndex++;
this.cmd("CreateLabel", tmpLabel1, rightSib.keys[0], this.getLabelX(rightSib, 0), rightSib.y)
this.cmd("CreateLabel", tmpLabel2, parentNode.keys[parentIndex], this.getLabelX(parentNode, parentIndex), parentNode.y)
this.cmd("SetForegroundColor", tmpLabel1, FOREGROUND_COLOR);
this.cmd("SetForegroundColor", tmpLabel2, FOREGROUND_COLOR);
this.cmd("Move", tmpLabel1, this.getLabelX(parentNode, parentIndex), parentNode.y);
this.cmd("Move", tmpLabel2, this.getLabelX(tree, tree.numKeys - 1), tree.y);
this.cmd("Step")
this.cmd("Delete", tmpLabel1);
this.cmd("Delete", tmpLabel2);
tree.keys[tree.numKeys - 1] = parentNode.keys[parentIndex];
parentNode.keys[parentIndex] = rightSib.keys[0];
this.cmd("SetText", tree.graphicID, tree.keys[tree.numKeys - 1], tree.numKeys - 1);
this.cmd("SetText", parentNode.graphicID, parentNode.keys[parentIndex], parentIndex);
if (!tree.isLeaf)
{
tree.children[tree.numKeys] = rightSib.children[0];
tree.children[tree.numKeys].parent = tree;
this.cmd("Disconnect", rightSib.graphicID, rightSib.children[0].graphicID);
this.cmd("Connect", tree.graphicID,
tree.children[tree.numKeys].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
tree.numKeys);
// TODO::CHECKME!
for (var i = 1; i < rightSib.numKeys + 1; i++)
{
this.cmd("Disconnect", rightSib.graphicID, rightSib.children[i].graphicID);
rightSib.children[i-1] = rightSib.children[i];
this.cmd("Connect", rightSib.graphicID,
rightSib.children[i-1].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
i-1);
}
}
for (i = 1; i < rightSib.numKeys; i++)
{
rightSib.keys[i-1] = rightSib.keys[i];
this.cmd("SetText", rightSib.graphicID, rightSib.keys[i-1], i-1);
}
this.cmd("SetText", rightSib.graphicID, "", rightSib.numKeys-1);
rightSib.numKeys--;
this.cmd("SetNumElements", rightSib.graphicID, rightSib.numKeys);
this.resizeTree();
this.cmd("SetText", this.messageID, "");
return tree;
}
BTree.prototype.stealFromLeft = function(tree, parentIndex)
{
var parentNode = tree.parent;
// Steal from left sibling
tree.numKeys++;
this.cmd("SetNumElements", tree.graphicID, tree.numKeys);
this.cmd("SetText", this.messageID, "Node has too few keys. Stealing from left sibling.");
for (i = tree.numKeys - 1; i > 0; i--)
{
tree.keys[i] = tree.keys[i-1];
this.cmd("SetText", tree.graphicID, tree.keys[i], i);
}
var leftSib = parentNode.children[parentIndex -1];
this.cmd("SetText", tree.graphicID, "", 0);
this.cmd("SetText", parentNode.graphicID, "", parentIndex - 1);
this.cmd("SetText", leftSib.graphicID, "", leftSib.numKeys - 1);
var tmpLabel1 = this.nextIndex++;
var tmpLabel2 = this.nextIndex++;
this.cmd("CreateLabel", tmpLabel1, leftSib.keys[leftSib.numKeys - 1], this.getLabelX(leftSib, leftSib.numKeys - 1), leftSib.y)
this.cmd("CreateLabel", tmpLabel2, parentNode.keys[parentIndex - 1], this.getLabelX(parentNode, parentIndex - 1), parentNode.y)
this.cmd("SetForegroundColor", tmpLabel1, FOREGROUND_COLOR);
this.cmd("SetForegroundColor", tmpLabel2, FOREGROUND_COLOR);
this.cmd("Move", tmpLabel1, this.getLabelX(parentNode, parentIndex - 1), parentNode.y);
this.cmd("Move", tmpLabel2, this.getLabelX(tree, 0), tree.y);
this.cmd("Step")
this.cmd("Delete", tmpLabel1);
this.cmd("Delete", tmpLabel2);
if (!tree.isLeaf)
{
for (var i = tree.numKeys; i > 0; i--)
{
this.cmd("Disconnect", tree.graphicID, tree.children[i-1].graphicID);
tree.children[i] =tree.children[i-1];
this.cmd("Connect", tree.graphicID,
tree.children[i].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
i);
}
tree.children[0] = leftSib.children[leftSib.numKeys];
this.cmd("Disconnect", leftSib.graphicID, leftSib.children[leftSib.numKeys].graphicID);
this.cmd("Connect", tree.graphicID,
tree.children[0].graphicID,
FOREGROUND_COLOR,
0, // Curve
0, // Directed
"", // Label
0);
leftSib.children[leftSib.numKeys] = null;
tree.children[0].parent = tree;
}
tree.keys[0] = parentNode.keys[parentIndex - 1];
this.cmd("SetText", tree.graphicID, tree.keys[0], 0);
parentNode.keys[parentIndex-1] = leftSib.keys[leftSib.numKeys - 1];
this.cmd("SetText", parentNode.graphicID, parentNode.keys[parentIndex - 1], parentIndex - 1);
this.cmd("SetText", leftSib.graphicID,"", leftSib.numKeys - 1);
leftSib.numKeys--;
this.cmd("SetNumElements", leftSib.graphicID, leftSib.numKeys);
this.resizeTree();
this.cmd("SetText", this.messageID, "");
return tree;
}
BTree.prototype.repairAfterDelete = function(tree)
{
if (tree.numKeys < this.min_keys)
{
if (tree.parent == null)
{
if (tree.numKeys == 0)
{
this.cmd("Step");
this.cmd("Delete", tree.graphicID);
this.treeRoot = tree.children[0];
if (this.treeRoot != null)
this.treeRoot.parent = null;
this.resizeTree();
}
}
else
{
var parentNode = tree.parent;
for (var parentIndex = 0; parentNode.children[parentIndex] != tree; parentIndex++);
if (parentIndex > 0 && parentNode.children[parentIndex - 1].numKeys > this.min_keys)
{
this.stealFromLeft(tree, parentIndex);
}
else if (parentIndex < parentNode.numKeys && parentNode.children[parentIndex + 1].numKeys > this.min_keys)
{
this.stealFromRight(tree,parentIndex);
}
else if (parentIndex == 0)
{
// Merge with right sibling
var nextNode = this.mergeRight(tree);
this.repairAfterDelete(nextNode.parent);
}
else
{
// Merge with left sibling
nextNode = this.mergeRight(parentNode.children[parentIndex-1]);
this.repairAfterDelete(nextNode.parent);
}
}
}
}
BTree.prototype.getLabelX = function(tree, index)
{
return tree.x - WIDTH_PER_ELEM * tree.numKeys / 2 + WIDTH_PER_ELEM / 2 + index * WIDTH_PER_ELEM;
}
BTree.prototype.resizeTree = function()
{
this.resizeWidths(this.treeRoot);
this.setNewPositions(this.treeRoot, this.starting_x, STARTING_Y);
this.animateNewPositions(this.treeRoot);
}
BTree.prototype.setNewPositions = function(tree, xPosition, yPosition)
{
if (tree != null)
{
tree.y = yPosition;
tree.x = xPosition;
if (!tree.isLeaf)
{
var leftEdge = xPosition - tree.width / 2;
var priorWidth = 0;
for (var i = 0; i < tree.numKeys+1; i++)
{
this.setNewPositions(tree.children[i], leftEdge + priorWidth + tree.widths[i] / 2, yPosition+HEIGHT_DELTA);
priorWidth += tree.widths[i];
}
}
}
}
BTree.prototype.animateNewPositions = function(tree)
{
if (tree == null)
{
return;
}
var i;
for (i = 0; i < tree.numKeys + 1; i++)
{
this.animateNewPositions(tree.children[i]);
}
this.cmd("Move", tree.graphicID, tree.x, tree.y);
}
BTree.prototype.resizeWidths = function(tree)
{
if (tree == null)
{
return 0;
}
if (tree.isLeaf)
{
for (var i = 0; i < tree.numKeys + 1; i++)
{
tree.widths[i] = 0;
}
tree.width = tree.numKeys * WIDTH_PER_ELEM + NODE_SPACING;
return tree.width;
}
else
{
var treeWidth = 0;
for (i = 0; i < tree.numKeys+1; i++)
{
tree.widths[i] = this.resizeWidths(tree.children[i]);
treeWidth = treeWidth + tree.widths[i];
}
treeWidth = Math.max(treeWidth, tree.numKeys * WIDTH_PER_ELEM + NODE_SPACING);
tree.width = treeWidth;
return treeWidth;
}
}
function BTreeNode(id, initialX, initialY)
{
this.widths = [];
this.keys = [];
this.children = [];
this.x = initialX;
this.y = initialY;
this.graphicID = id;
this.numKeys = 1;
this.isLeaf = true;
this.parent = null;
this.leftWidth = 0;
this.rightWidth = 0;
}
var currentAlg;
function init()
{
var animManag = initCanvas();
currentAlg = new BTree(animManag, canvas.width, canvas.height);
}