Trees
A tree is a hierarchical data structure that consists of nodes connected by edges. It is one of the most fundamental data structures used to organize data in a way that enables efficient searching, sorting, and many other operations. Trees are particularly useful for representing hierarchical relationships, such as file systems, organizational structures, and decision-making processes.

Key Concepts of Trees:

Node: Each element in the tree is called a node. It stores data and may have references (or pointers) to other nodes. Root: The topmost node in a tree. It is the only node in the tree that has no parent. All other nodes are descendants of the root.
Parent: A node that has one or more child nodes.
Child: A node that is a descendant of another node, i.e., a node that is directly linked from a parent node.
Leaf: A node that does not have any children. It is at the lowest level of the tree.
Subtree: A tree that consists of a node and all its descendants.
Depth: The distance from the root node to a given node (number of edges from the root).
Height: The longest path from a node to a leaf node (number of edges from the node to the furthest leaf).
Level: The level of a node is the number of edges from the root to the node.
Edge: The connection between two nodes.