![Complete binary tree](https://kumkoniak.com/10.jpg)
That’s why we can solve many tree problems using recursion: Assuming we knew the solution to the smaller subtree, how could we combine it to get the final answer? Similarly, we can also think tree as a particular version of a directed acyclic graph (A graph with no cycle). We can think tree as a recursive object, defined as a collection of smaller trees starting at a root node. Good examples of a tree are data stored in a computer file system, hierarchical records of employees in a company, recursion tree structure, etc.
![complete binary tree complete binary tree](https://examradar.com/wp-content/uploads/2016/10/Figure-5.2.4.-Examples-of-complete-and-incomplete-binary-trees.png)
It is made up of a finite set of elements called nodes.
![complete binary tree complete binary tree](https://image.slidesharecdn.com/completebinarytreeandheap-191104120036/95/complete-binary-tree-and-heap-14-638.jpg)
The tree is a non-linear data structure that stores data in the form of a hierarchical structure.
![Complete binary tree](https://kumkoniak.com/10.jpg)