AvlTrees - Algoviz Wiki

Works

Yes

Description

A collection of exercises related to searching, inserting into, and deleting from AVL Trees. User points at the appropriate node, or drags-and-drops nodes as appropriate.

Evaluation

This works well as an exercise, since the mechanics are at the right level of granularity to gain understanding without becoming too repetitive. The exercises are easy to use. Several exercises are included.

Canned Data; Predictions

Lecture Aid; Self Study; Lab Exercise

Screenshots

Videos

References

The link above takes you to the Trakla exercise index. Click on the "AVL-tree insertion" link in the middle column under "Search Trees". The AVL AV is implemented as a Java applet and so should start up when you load the page. You will see a "stream of keys" at the top, in blue. Take the first one and drag it to the correct location in the AVL tree (in the green box). In particular, you must drag the letter to the proper little circle that correspond to the leaf nodes. If the tree is unbalanced after adding the node, then you will click the proper button below to trigger a rotation. You can click on the "Instructions" tab at the top of the applet for some instructions, and the pseudocode in the left pane will explain how to determine what to do if the tree is unbalanced. You can see what the correct series of steps would be by clicking on "Model Answer". You can have the system tell you how well you did by clicking on "Grade".

First Visited

2008-07-29

Last Visited

2008-07-29

Last Updated

2006-01-25

Topic

Community

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http://people.ksp.sk/~kuko/bak/

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Kovac's Visualisation of AVL trees

Recommendation

Not Recommended

Link

Delivery Method

Java Applet

License

Unavailable

Language

English; Slovak

Author

Kubo Kovac

Institution

Comenius University, Slovakia

Project

Kovac's Tree Project

Works

Yes

Description

This AV shows various search trees such as AVL, BST, B tree, red-black tree, AA tree, skiplist, heap, treap, scapegoat tree and splay tree. It demonstrates insertion, deletion and search. Users can start with randomly generated input dataset or user's own data. For the data structuers where this is relevent, it provides balance factors such as ‘+’, ‘-‘ and ‘.’ by the nodes.

Evaluation

Strengths: The best feature of this tool is to provide many search trees. This may allow learners to identify how the search trees work by comparison with each other. Randomly generated dataset lets users quickly see the structure of the tree. Users can also construct their own data set. Weaknesses: Like many tree AVs, it just shows the result of the insert or delete operation, without explaining how it works. What is neeed is good textual explanation about each search structure and documentation explaining basic key concepts such as balance factors, re-balancing, etc. The text size of balance factors on the nodes is too small to be recognized (you need to use the "big" version of the applet to see them at all).

Exploring the Concept; Comparison; Lecture Aid

Screenshots

Videos

References

First Visited

2007

Last Visited

2010-02-16

Last Updated

2007

Topic

Community

Average rating:	2.0
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http://dbs.mathematik.uni-marburg.de/research/projects/dsn/

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Data Structures Navigator - Binary Search Trees - AVL

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

Unavailable

Language

English

Author

Jens-Peter Dittrich; Jochen van den Bercken; Tobias Schäfer; Marcus Klein

Institution

Phillips-University of Marburg

Project

Data Structure Navigator

Works

Yes

Description

User enters data values to insert/find/delete in AVL tree. Smooth animation of the movements for nodes. Shows balance factors for nodes.

Evaluation

Easy to use interface, nice graphics. The main problem is that there is no explanation of what is going on. Showing balance factors is helpful. Unfortunately, there is rather an abrupt transition from computing balance factors (it never quite finishes doing this) and the actual rotation. The rotation takes place as soon as the relevant node is reached, without showing the balance value that triggered the rotation. The rotation is also rather abrupt, and only shows the final result with no indication of the steps involved that lead to the result.

Step Control; Animation; User Data

Lecture Aid; Self Study

Screenshots

Videos

References

First Visited

2006-09-01

Last Visited

2008-07-16

Last Updated

2000-07-31

Topic

Community

Average rating:	3.0
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http://www.cs.usfca.edu/galles/visualization/download.html

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Data Structure Visualization - AVL Tree

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

Unlicensed Sourcecode

Language

English

Author

David Galles

Institution

University of San Francisco

Project

Data Structure Visualization

Works

Yes

Description

This visualization demonstrates the behavior of an AVL tree. Users can insert and delete values. Rotations are shown.

Evaluation

The visualization shows the AVL-tree with the height of the subtree in every node. The user is allowed to enter data to insert, delete, or search items to/from the tree. The search path in every operation is visualized and rotations are smoothly animated. The speed of the animation can be changed by the user. The main problem is that there is no code and no explanation for what is happening. Rotations are shown... but it is an animation that the user has no control over or detailed explanation of the steps.

Animation Only; User Data

Lecture Aid; Debugging

Screenshots

Videos

References

First Visited

2006-09-01

Last Visited

2008-07-01

Last Updated

2006-04-05

Topic

Community

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http://www.cs.jhu.edu/~goodrich/dsa/trees/avltree.html

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Animated AVL Tree

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unlicensed Sourcecode

Language

English

Author

John Kloss; Michael Goodrich

Institution

Johns Hopkins University

Project

Goodrich's Collection

PartOfCollection

Works

Yes

Description

This AV tool is a Java applet which graphically shows how the AVL tree works along with decent animations. It provides insert, delete and search operations for users. It shows textual explanation at the bottom of applet and a nice animation.

Evaluation

Intended to go with a data structures textbook, this animation (like its sibling "Animated Binary Tree") can stand alone as well. This one is somewhat harder to follow since it moves so quickly; it is especially difficult to understand the rotation/balance step. Also, it contains a rather serious bug: deletes do not re-balance the tree. Besides, one of its weaknesses is no speed control which makes it hard to follow what's happening. It has too short explanation at the bottom of applet to make learners comprehend sufficiently. In terms of input data, it does not provide randomly generated data set that makes it easy for intermediate users to start from the middle of learning process.

Teaching the Concept; Exploring the Concept

Screenshots

Videos

References

First Visited

2006-01-24

Last Visited

2006-01-24

Last Updated

1997-08-05

Topic

Community

Average rating:	3.0
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http://www.cse.iitk.ac.in/users/dsrkg/cs210/applets/AVLtree/avl.html

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Ghosh - AVL Tree

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

R. K. Ghosh

Institution

Indian Institute of Technology, Kanpur

Project

Ghosh's Collection

PartOfCollection

Works

Yes

Description

User can insert or delete elements into the AVL tree and then watch how step-by-step operations for inserting/deleting elements.

Evaluation

Although the first impression of this tool is not so good, it handles quite well the visualization of red black tree construction. Visualization controls are quite poor and unintuitive: some buttons have to be pressed several times and it’s not always clear when you can insert a new element into the tree. Also the user interface could use some polishing: the control buttons are confusedly laid out and the whole background is strangely pink. Still, the visualization is quite nicely implemented. The animation is slow enough and it flows quite smoothly. Some explanations of events happening during tree construction would be useful. It would be nice to be able to control the speed of the animation portions, which often seem too slow.

Step Control; User Data

Lecture Aid; Self Study; Debugging

Screenshots

Videos

References

First Visited

2006-11-06

Last Visited

2008-07-16

Last Updated

2001-08-12

Topic

Community

Average rating:	2.0
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http://webpages.ull.es/users/jriera/Docencia/AVL/AVL%20tree%20applet.htm

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AVL Tree Applet

Recommendation

Recommended

Link

Delivery Method

Java Applet

License

Language

English

Author

Arsen Gogeshvili

Institution

University of LA Laguna

Project

StandAlone

StandAlone

Works

Unavailable

Description

On its first applet interface, this visualization shows randomly generated input and then allows user to add user defined input. In addition, it has tree size control options; sound options that work seamlessly with all the animations; the animation speed control options. Textual description of each operation as well as pre and post-order traversals are provided in the visualization. Other fancy options like shape control feature and direction control features are also included. Moreover, images on command buttons help users use this tool intuitively. The visualization also shows the basic splay operation for comparison to AVL.

Evaluation

This visualization provides several options like user defined data, step-wise speed control, description of each operation with valuable visual effects so that a user can fit the tool to his/her preference. It also provides sound effects and animation effect, in particular, rotation signs before executing operations. This application is highly intuitive with simple and smooth animation. The descriptions after the operation has completed give an insight into what operations the Algorithm visualization went through. The write up provided by author for the algorithm in general is also insightful. Interface provides options to insert node, delete node and find nodes in predetermined or user defined dataset. It also provides good control over the speed of animation. Despite its neat design, the visualization is missing some options. The next button is missing (hence no step by step trace capability) which could have been an added advantage. The layout is pretty decent but it cannot support a large set of numbers. It shows the basic splay operation which was missing in earlier visualizations. But sadly, one cannot control the pacing of the splay operation and it splays the node selected to the root through a series of fast visual iterations. One needs to control the pace of these iterations to have better understanding of the AVL concept which forms the basis of AVL. Further, once we press “AVL” button, there is no getting back. One has to have a basic knowledge of the BSTs and Self Balancing trees to work with this visualization and this cannot be given to novices who have not taken any Data Structures course till now. Though a beef-up of the basic operations by providing pace control, “Previous” and “Next” Buttons, and a short text box that explains what happened in a particular iteration would make this AV a very potent and useful tool for all user groups.

Teaching the Concept; Exploring the Concept

Screenshots

Videos

References