Trees

What is a Tree?

The tree data structure mimics mother nature's tree. It is generally non-linear but is not inter-connected (is not a network).

Key Concepts:

The most important concept is node
There is one root node (or starting node or top node)
Each node has zero or more child nodes (think of the pointers to those nodes as branches)
Many trees have a defined number of children (binary = 2, ternary = 3, ...)
Child nodes may be null
Nodes hold data (e.g., customers, employees, etc) -- for simplicity we are showing integer data (e.g., 50, 20, 10, ...) in the diagram

A Simple Tree

                 50
                  |
          --------+--------
          |               |
          20              70
     -----+-----      -----+
     |         |      |
     10       40      60
         -----+
         |
        30

Directory Example

A computer directory tree is a familiar tree

+---jdk-11.0.2
|   +---bin
|   |   \---server
|   +---conf
|   |   +---management
|   |   \---security
|   |       \---policy
|   |           +---limited
|   |           \---unlimited
|   +---include
|   |   \---win32
|   |       \---bridge
|   +---jmods
|   \---lib
|       +---jfr
|       +---security
|       \---server