418 行
11 KiB
JavaScript
418 行
11 KiB
JavaScript
// Copyright 2011 David Galles, University of San Francisco. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other materials
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// provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND ANY EXPRESS OR IMPLIED
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// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
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// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// The views and conclusions contained in the software and documentation are those of the
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// authors and should not be interpreted as representing official policies, either expressed
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// or implied, of the University of San Francisco
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function ClosedHash(am, w, h)
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{
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this.init(am, w, h);
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}
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var ARRAY_ELEM_WIDTH = 90;
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var ARRAY_ELEM_HEIGHT = 30;
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var ARRAY_ELEM_START_X = 50;
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var ARRAY_ELEM_START_Y = 100;
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var ARRAY_VERTICAL_SEPARATION = 100;
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var CLOSED_HASH_TABLE_SIZE = 29;
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var ARRAY_Y_POS = 350;
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var INDEX_COLOR = "#0000FF";
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var MAX_DATA_VALUE = 999;
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var HASH_TABLE_SIZE = 13;
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var ARRAY_Y_POS = 350;
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var INDEX_COLOR = "#0000FF";
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ClosedHash.prototype = new Hash();
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ClosedHash.prototype.constructor = ClosedHash;
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ClosedHash.superclass = Hash.prototype;
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ClosedHash.prototype.init = function(am, w, h)
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{
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var sc = ClosedHash.superclass;
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var fn = sc.init;
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this.elements_per_row = Math.floor(w / ARRAY_ELEM_WIDTH);
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fn.call(this,am, w, h);
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//Change me!
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this.nextIndex = 0;
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//this.POINTER_ARRAY_ELEM_Y = h - POINTER_ARRAY_ELEM_WIDTH;
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this.setup();
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}
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ClosedHash.prototype.addControls = function()
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{
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ClosedHash.superclass.addControls.call(this);
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var radioButtonList = addRadioButtonGroupToAlgorithmBar(["Linear Probing: f(i) = i",
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"Quadratic Probing: f(i) = i * i",
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"Double Hashing: f(i) = i * hash2(elem)"],
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"CollisionStrategy");
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this.linearProblingButton = radioButtonList[0];
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this.linearProblingButton.onclick = this.linearProbeCallback.bind(this);
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this.quadraticProbingButton = radioButtonList[1];
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this.quadraticProbingButton.onclick = this.quadraticProbeCallback.bind(this);
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this.doubleHashingButton = radioButtonList[2];
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this.doubleHashingButton.onclick = this.doubleHashingCallback.bind(this);
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this.linearProblingButton.checked = true;
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this.currentHashingTypeButtonState = this.linearProblingButton;
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// Add new controls
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}
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ClosedHash.prototype.changeProbeType = function(newProbingType)
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{
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if (newProbingType == this.linearProblingButton)
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{
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this.linearProblingButton.checked = true;
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this.currentHashingTypeButtonState = this.linearProblingButton;
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for (var i = 0; i < this.table_size; i++)
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{
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this.skipDist[i] = i;
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}
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}
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else if (newProbingType == this.quadraticProbingButton)
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{
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this.quadraticProbingButton.checked = true;
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this.currentHashingTypeButtonState = this.quadraticProbingButton;
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for (var i = 0; i < this. table_size; i++)
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{
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this.skipDist[i] = i * i;
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}
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}
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else if (newProbingType == this.doubleHashingButton)
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{
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this.doubleHashingButton.checked = true;
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this.currentHashingTypeButtonState = this.doubleHashingButton;
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}
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this.commands = this.resetAll();
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return this.commands;
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}
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ClosedHash.prototype.quadraticProbeCallback = function(event)
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{
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if (this.currentHashingTypeButtonState != this.quadraticProbingButton)
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{
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this.implementAction(this.changeProbeType.bind(this),this.quadraticProbingButton);
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}
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}
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ClosedHash.prototype.doubleHashingCallback = function(event)
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{
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if (this.currentHashingTypeButtonState != this.doubleHashingButton)
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{
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this.implementAction(this.changeProbeType.bind(this),this.doubleHashingButton);
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}
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}
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ClosedHash.prototype.linearProbeCallback = function(event)
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{
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if (this.currentHashingTypeButtonState != this.linearProblingButton)
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{
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this.implementAction(this.changeProbeType.bind(this),this.linearProblingButton);
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}
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}
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ClosedHash.prototype.insertElement = function(elem)
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{
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this.commands = new Array();
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this.cmd("SetText", this.ExplainLabel, "Inserting element: " + String(elem));
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var index = this.doHash(elem);
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index = this.getEmptyIndex(index, elem);
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this.cmd("SetText", this.ExplainLabel, "");
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if (index != -1)
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{
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var labID = this.nextIndex++;
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this.cmd("CreateLabel", labID, elem, 20, 25);
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this.cmd("Move", labID, this.indexXPos[index], this.indexYPos[index] - ARRAY_ELEM_HEIGHT);
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this.cmd("Step");
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this.cmd("Delete", labID);
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this.cmd("SetText", this.hashTableVisual[index], elem);
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this.hashTableValues[index] = elem;
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this.empty[index] = false;
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this.deleted[index] = false;
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}
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return this.commands;
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}
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ClosedHash.prototype.resetSkipDist = function(elem, labelID)
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{
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var skipVal = 7 - (this.currHash % 7);
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this.cmd("CreateLabel", labelID, "hash2("+String(elem) +") = 1 - " + String(this.currHash) +" % 7 = " + String(skipVal), 20, 45, 0);
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this.skipDist[0] = 0;
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for (var i = 1; i < this.table_size; i++)
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{
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this.skipDist[i] = this.skipDist[i-1] + skipVal;
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}
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}
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ClosedHash.prototype.getEmptyIndex = function(index, elem)
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{
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if (this.currentHashingTypeButtonState == this.doubleHashingButton)
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{
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this.resetSkipDist(elem, this.nextIndex++);
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}
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var foundIndex = -1;
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for (var i = 0; i < this.table_size; i++)
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{
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var candidateIndex = (index + this.skipDist[i]) % this.table_size;
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this.cmd("SetHighlight", this.hashTableVisual[candidateIndex], 1);
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this.cmd("Step");
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this.cmd("SetHighlight", this.hashTableVisual[candidateIndex], 0);
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if (this.empty[candidateIndex])
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{
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foundIndex = candidateIndex;
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break;
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}
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}
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if (this.currentHashingTypeButtonState == this.doubleHashingButton)
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{
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this.cmd("Delete", --this.nextIndex);
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}
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return foundIndex;
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}
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ClosedHash.prototype.getElemIndex = function(index, elem)
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{
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if (this.currentHashingTypeButtonState == this.doubleHashingButton)
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{
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resetSkipDist(elem, this.nextIndex++);
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}
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var foundIndex = -1;
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for (var i = 0; i < this.table_size; i++)
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{
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var candidateIndex = (index + this.skipDist[i]) % this.table_size;
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this.cmd("SetHighlight", this.hashTableVisual[candidateIndex], 1);
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this.cmd("Step");
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this.cmd("SetHighlight", this.hashTableVisual[candidateIndex], 0);
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if (!this.empty[candidateIndex] && this.hashTableValues[candidateIndex] == elem)
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{
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foundIndex= candidateIndex;
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break;
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}
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else if (this.empty[candidateIndex] && !this.deleted[candidateIndex])
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{
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break; }
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}
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if (this.currentHashingTypeButtonState == this.doubleHashingButton)
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{
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this.cmd("Delete", --this.nextIndex);
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}
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return foundIndex;
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}
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ClosedHash.prototype.deleteElement = function(elem)
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{
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this.commands = new Array();
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this.cmd("SetText", this.ExplainLabel, "正在删除元素： " + elem);
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var index = this.doHash(elem);
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index = this.getElemIndex(index, elem);
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if (index > 0)
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{
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this.cmd("SetText", this.ExplainLabel, "正在删除元素： " + elem + " 元素已删除");
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this.empty[index] = true;
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this.deleted[index] = true;
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this.cmd("SetText", this.hashTableVisual[index], "<deleted>");
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}
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else
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{
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this.cmd("SetText", this.ExplainLabel, "正在删除元素： " + elem + " Element not in table");
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}
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return this.commands;
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}
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ClosedHash.prototype.findElement = function(elem)
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{
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this.commands = new Array();
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this.cmd("SetText", this.ExplainLabel, "正在搜索元素： " + elem);
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var index = this.doHash(elem);
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var found = this.getElemIndex(index, elem) != -1;
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if (found)
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{
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this.cmd("SetText", this.ExplainLabel, "正在搜索元素： " + elem+ " 已找到！")
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}
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else
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{
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this.cmd("SetText", this.ExplainLabel, "正在搜索元素： " + elem+ " 未找到！")
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}
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return this.commands;
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}
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ClosedHash.prototype.setup = function()
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{
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this.table_size = CLOSED_HASH_TABLE_SIZE;
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this.skipDist = new Array(this.table_size);
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this.hashTableVisual = new Array(this.table_size);
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this.hashTableIndices = new Array(this.table_size);
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this.hashTableValues = new Array(this.table_size);
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this.indexXPos = new Array(this.table_size);
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this.indexYPos = new Array(this.table_size);
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this.empty = new Array(this.table_size);
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this.deleted = new Array(this.table_size);
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this.ExplainLabel = this.nextIndex++;
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this.commands = [];
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for (var i = 0; i < this.table_size; i++)
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{
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this.skipDist[i] = i; // Start with linear probing
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var nextID = this.nextIndex++;
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this.empty[i] = true;
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this.deleted[i] = false;
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var nextXPos = ARRAY_ELEM_START_X + (i % this.elements_per_row) * ARRAY_ELEM_WIDTH;
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var nextYPos = ARRAY_ELEM_START_Y + Math.floor(i / this.elements_per_row) * ARRAY_VERTICAL_SEPARATION;
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this.cmd("CreateRectangle", nextID, "", ARRAY_ELEM_WIDTH, ARRAY_ELEM_HEIGHT,nextXPos, nextYPos)
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this.hashTableVisual[i] = nextID;
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nextID = this.nextIndex++;
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this.hashTableIndices[i] = nextID;
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this.indexXPos[i] = nextXPos;
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this.indexYPos[i] = nextYPos + ARRAY_ELEM_HEIGHT
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this.cmd("CreateLabel", nextID, i,this.indexXPos[i],this.indexYPos[i]);
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this.cmd("SetForegroundColor", nextID, INDEX_COLOR);
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}
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this.cmd("CreateLabel", this.ExplainLabel, "", 10, 25, 0);
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animationManager.StartNewAnimation(this.commands);
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animationManager.skipForward();
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animationManager.clearHistory();
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this.resetIndex = this.nextIndex;
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}
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ClosedHash.prototype.resetAll = function()
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{
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this.commands = ClosedHash.superclass.resetAll.call(this);
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for (var i = 0; i < this.table_size; i++)
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{
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this.empty[i] = true;
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this.deleted[i] = false;
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this.cmd("SetText", this.hashTableVisual[i], "");
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}
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return this.commands;
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// Clear array, etc
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}
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// NEED TO OVERRIDE IN PARENT
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ClosedHash.prototype.reset = function()
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{
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for (var i = 0; i < this.table_size; i++)
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{
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this.empty[i]= true;
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this.deleted[i] = false;
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}
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this.nextIndex = this.resetIndex ;
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ClosedHash.superclass.reset.call(this);
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}
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function resetCallback(event)
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{
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}
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ClosedHash.prototype.disableUI = function(event)
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{
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ClosedHash.superclass.disableUI.call(this);
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this.linearProblingButton.disabled = true;
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this.quadraticProbingButton.disabled = true;
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this.doubleHashingButton.disabled = true;
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}
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ClosedHash.prototype.enableUI = function(event)
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{
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ClosedHash.superclass.enableUI.call(this);
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this.linearProblingButton.disabled = false;
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this.quadraticProbingButton.disabled = false;
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this.doubleHashingButton.disabled = false;
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}
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var currentAlg;
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function init()
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{
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var animManag = initCanvas();
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currentAlg = new ClosedHash(animManag, canvas.width, canvas.height);
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}
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