Trees

Tree

A hierarchical structure represented graphically with elements or nodes linked to successors.

Node

An element in a tree that can have links to other nodes (successors).

Root

The top node of a tree that has no parent.

Branch/Edge/Line/Path

The links connecting a node to its successors.

Child Node

A successor of a node in a tree.

Parent

The predecessor of a node in a tree.

Binary Tree

A tree where each node has at most two child nodes.

Sibling

Nodes that share the same parent.

Leaf Node

A node that has no child nodes, also known as an external node.

Internal Node

A node that has one or more child nodes.

Subtree

A tree that exists within another tree.

Level

A measure of a node's distance from the root.

Depth

The highest level of a tree.

Degree

The number of child nodes in a subtree.

Breadth-First Search

A traversal method where nodes are visited level by level.

Depth-First Search

A traversal method that explores as far as possible along each branch before backtracking.

Inorder Traversal

A depth-first method visiting nodes in the order of Left, Root, Right.

Preorder Traversal

A depth-first method visiting nodes in the order of Root, Left, Right.

Postorder Traversal

A depth-first method visiting nodes in the order of Left, Right, Root.

Inorder Starting Point

Start with the bottommost left subtree. Once the root in Level 0 is visited, proceed to the bottommost right subtree.

Preorder Starting Point

Start with the root level in level 0 then continue with the left subtree.

Postorder Starting Point

Start with the bottommost left subtree then proceed to the other subtrees.