Philiprehberger.TreeStructure

Generic tree data structure with traversal, serialization, subtree mutation, lowest common ancestor, and flat-to-tree conversion.

Installation

dotnet add package Philiprehberger.TreeStructure

Usage

using Philiprehberger.TreeStructure;

var root = TreeNode<string>.Create("root");
var child1 = root.AddChild("child-1");
var child2 = root.AddChild("child-2");
var grandchild = child1.AddChild("grandchild-1");

Console.WriteLine(root.IsRoot);       // True
Console.WriteLine(grandchild.IsLeaf); // True
Console.WriteLine(grandchild.Depth);  // 2

Traverse

using Philiprehberger.TreeStructure;

// Depth-first (default)
foreach (var node in root.Traverse())
{
    Console.WriteLine(node.Value);
}

// Breadth-first
foreach (var node in root.Traverse(TraversalMode.BreadthFirst))
{
    Console.WriteLine(node.Value);
}

// Depth-limited traversal (root + children only)
foreach (var node in root.Traverse(TraversalMode.DepthFirst, maxDepth: 1))
{
    Console.WriteLine(node.Value);
}

// Find and path
var found = root.Find(v => v == "grandchild-1");
var path = found?.PathToRoot(); // [grandchild-1, child-1, root]

Flat-to-Tree Conversion

using Philiprehberger.TreeStructure;

var items = new[]
{
    new { Id = 1, ParentId = (int?)null, Name = "Root" },
    new { Id = 2, ParentId = (int?)1,    Name = "Child A" },
    new { Id = 3, ParentId = (int?)1,    Name = "Child B" },
    new { Id = 4, ParentId = (int?)2,    Name = "Grandchild" },
};

var tree = TreeBuilder.FromFlat(items, x => x.Id, x => x.ParentId);
Console.WriteLine(tree.ToTreeString());

Serialization

using Philiprehberger.TreeStructure;

var root = TreeNode<string>.Create("root");
root.AddChild("child-1");
root.AddChild("child-2");

// Serialize to JSON
string json = root.Serialize();
// {"value":"root","children":[{"value":"child-1","children":[]},{"value":"child-2","children":[]}]}

// Deserialize back to a tree
var restored = TreeNode<string>.Deserialize(json);

Subtree Mutation

using Philiprehberger.TreeStructure;

var root = TreeNode<string>.Create("root");
var child1 = root.AddChild("child-1");
var child2 = root.AddChild("child-2");
var grandchild = child1.AddChild("grandchild");

// Move a node to a new parent
grandchild.MoveTo(child2);

// Remove a node from the tree
child1.Remove();

// Positional insertion
var newNode = TreeNode<string>.Create("new");
newNode.InsertBefore(child2);
newNode.InsertAfter(child2);

Lowest Common Ancestor

using Philiprehberger.TreeStructure;

var root = TreeNode<string>.Create("root");
var child1 = root.AddChild("child-1");
var child2 = root.AddChild("child-2");
var gc1 = child1.AddChild("gc-1");
var gc2 = child2.AddChild("gc-2");

var lca = TreeNode<string>.FindLCA(gc1, gc2); // root
var lca2 = TreeNode<string>.FindLCA(child1, gc1); // child-1

API

Type	Member	Description
TreeNode<T>	Create(T value)	Creates a new root node
TreeNode<T>	AddChild(T value)	Adds a child node and returns it
TreeNode<T>	Value	Gets the stored value
TreeNode<T>	Parent	Gets the parent node or null
TreeNode<T>	Children	Gets the read-only list of children
TreeNode<T>	IsRoot / IsLeaf	Checks root or leaf status
TreeNode<T>	Depth	Gets the depth from the root
TreeNode<T>	Traverse(TraversalMode, int?)	Enumerates nodes in DFS or BFS order with optional depth limit
TreeNode<T>	Find(predicate)	Finds the first matching node
TreeNode<T>	FindAll(predicate)	Finds all matching nodes
TreeNode<T>	PathToRoot()	Returns nodes from this node to the root
TreeNode<T>	Remove()	Detaches node from its parent
TreeNode<T>	MoveTo(TreeNode<T>)	Moves node and subtree to a new parent
TreeNode<T>	InsertBefore(TreeNode<T>)	Inserts node before the specified sibling
TreeNode<T>	InsertAfter(TreeNode<T>)	Inserts node after the specified sibling
TreeNode<T>	Serialize(JsonSerializerOptions?)	Serializes tree to JSON string
TreeNode<T>	Deserialize(string, JsonSerializerOptions?)	Deserializes JSON string to tree
TreeNode<T>	FindLCA(TreeNode<T>, TreeNode<T>)	Finds lowest common ancestor of two nodes
TreeBuilder	FromFlat<T, TKey>(...)	Builds a tree from a flat collection
TreeExtensions	Flatten<T>(node)	Flattens tree values into a sequence
TreeExtensions	Count<T>(node)	Counts total nodes in the subtree
TreeExtensions	Height<T>(node)	Calculates the height of the subtree
TreeExtensions	ToTreeString<T>(node)	Renders an indented text representation
TraversalMode	DepthFirst / BreadthFirst	Traversal strategy enum values

Development

dotnet build src/Philiprehberger.TreeStructure.csproj --configuration Release

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License

MIT