sergatgh / solo.binarytree

Binary tree parser is a simple project developed for purpose of deserializing binary tree from a text file or a string.

Binary Tree Parser

Binary tree parser is a simple project developed for purpose of deserializing binary tree from a text file or a string. Developing this project, next goals were claimed:

• Read binary tree from a file using API:

public static Tree BuildTree (StreamReader reader);

• Required support for format (# - stays for null):

root, left, right
left, subnode, #
right, #, subnode

• Parsing file, algorythm should use as minimum iterations as possible
• If algorythm cannot parse a file for any reason it should be able to describe the reason

Tree Class Description

Tree class is a main file used across the project and represents a binary tree with links to Left, Right and Parent nodes. And of-course there is a data property represented by a .NET String class.

Creating a tree

Tree creation is hidden by the factory method located in the same class, called Create and accepting a string data. Calling a factory method will return you a tree creation result. Result can contain successfully created tree if indicator IsSuccess returns true or an error message if indicator IsFailure was set. Let's see this in example:

var createTreeResult = Tree.Create("data");

if (createTreeResult.IsFailure)
{
    Console.WriteLine("Creating a tree an error occured: {0}.", createTreeResult.FailureMessage);
}

Console.WriteLine("A tree was successfully created with data: {0}.", createTreeResult.Result.Data)

Specifying children

Tree class itself has two methods for children maintenance. A method OverrideNode allows to override any of already existing nodes by using reference to another tree and AddNode allows to create a new node from String data and add it to the current tree. Let's see an example:

public void MyLogic(Tree root, Tree randomNode)
{

    // Override existing node in tree. May produce an error if randomNode already has a parent.
    var overrideNodeResult = root.OverrideNode(randomNode, BinaryChildrenEnum.Left);
    
    // Add node and override it instead of right node. Could return an error if creation of new node were not passed.
    var addNodeResult = root.AddNode("rightNode", BinaryChildrenEnum.Right);
    
    // Indicate a full success by providing result to console.
    if (overrideNodeResult.IsSuccess && addNodeResult.IsSuccess)
    {
        Console.WriteLine("Tree populated with nodes successfully.");
    }
}

API Description

API has several methods dedicated to build a tree from string representation:

• The simpliest way to try things out is to copy the string above and pass it to BuildTreeByStringInput overload, like this:

var input = 
@"root, left, right
left, subnode, #
right, #, subnode";

Tree result = Api.BuildTreeByStringInput(input);

• The same tree you can create by putting an input into a text file and calling a BuildTreeByFilePath overload like this:

var path = "C:\\data.txt";
Tree result = Api.BuildTreeByFilePath(path);

• Pro-mode is when you care about streams yourself, for files we have BuildTree(StreamReader streamReader) overload, use it like this:

var path = "C:\\data.txt";
using (StreamReader streamReader = new StreamReader(path))
{
    var tree = Api.BuildTree(streamReader);
}

• Pro-mode is also when you know that StreamReader is inherited from TextReader as other classes like StringReader and for this purpose we have BuildTree(TextReader textReader) overload, don't hesitate to use it like this:

var input = 
@"root, left, right
left, subnode, #
right, #, subnode";

using (TextReader streamReader = new StringReader(input))
{
    var tree = Api.BuildTree(streamReader);
}

Test Results

According to the tests, which you can find in Performance Tests File, an algorythm parsing tree has next results:

• Parsing from memory 200.000+ nodes takes ~3 seconds, acceptance criteria is 6 seconds
• Parsing from file on the HDD 200.000+ nodes takes ~11 seconds, acceptance criteria is 13 seconds

Known Issues

Out of memory exception

When you try to deserialize a tree of 400.000+ nodes program complains that it has no so much memory to use. An issue brought by parser and in most cases is thrown in "Create Tree From Parsed Values file".

Possible cycling references

🙀 OMG, this is not a tree when there are cycles in graph, for more information, please reference Wikipedia Page.

The main reason why cyclic references are possible is that there are no check when adding a child node, so possible solutions can be:

• Creating a global validator, so to check the tree when it is created;
• Creating a tree manager which will have all data in one place and will be able to quickly resolve an error;

Wat? This project is not ideal? 😒

Yes, this project is not ideal 😜 , so you're welcome to contribute. Use these sections to bring your ideas to this project:

• Issues section of this repository where you can suggest your ideas;
• Pull Request where you can suggest your code.