Trees are hierarchical data structures, its abstract data type, made up of nodes or vertices and edges without having any cycle.
- The node at the top of the tree is called root.
- Any node that has one edge upward to a node
- The node below a given node connected by its edge downward
- The node which does not have any child node
- The level of a node represents the generation of a node. If the root node is at level 0, then its next child node is at level 1, its grandchild is at level 2, and so on.
- Height is considered as is the maximum number of nodes on the root to leaf path
- Subtree represents the descendants of a node- which has at lease one parent and child relationship.