Table of contents

Introduction

Stack

Tree

Difference between Stacks and Trees

4.1.

List of Top Stacks Questions

4.2.

List of Top Trees Questions

Frequently Asked Questions(FAQs)

5.1.

What type of data structures(Linear or Non-Linear) are Stacks and Trees?

5.2.

What is the insertion complexity for a node in a binary tree and stack?

Conclusion

Last Updated: Mar 27, 2024

Difference Between Stack and Tree

Author Firdausia Fatima

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Introduction

Acing a tech interview begins months, if not years before the interview takes place. There's a long list of required topics, such as operating systems, databases, and system design. However, one of the most important topics among all is data structures.

Data structures are just a way of storing data so that it may be accessed and modified quickly. There are many sorts of data structures, each of which is appropriate for a specific application. We'll look at two of these DS today: Stack and Tree. So let's get this party started.

Stack

Stack is a linear data structure with three major operations- PUSH, POP, and TOP for Insertion, deletion, and retrieving the top element, respectively.

Consider an empty long rectangular box containing some books. Suppose you bought a new book and put it in the box on top of the stack of books you already had. Which book do you think you'll be able to get out of the box first? It's, of course, the last book you inserted. This is what a stack looks like. The last element you inserted will be the first to pop out of the stack, i.e., it follows the LIFO(Last in, first out) property.

Diagrammatic Representation of a Stack

Tree

A tree is a nonlinear data structure that can be best described recursively. It consists of NODES—such that.

Each tree has a root node that can have zero or more child nodes.
Each child node can have one or more children, and so forth.
The node which has no child nodes is called a leaf node.

Every node has a DATA element and a list of pointers to child nodes.

Some special types of trees are:

Binary Tree: Binary Tree is a tree where each node can have a maximum of two children ‘LEFT’ and ‘RIGHT’.

Example

Binary Search Tree: A binary search tree is a binary tree in which each node's value is greater than all nodes values in the left subtree and smaller than all nodes values in the right subtree.

Example

Balanced and Unbalanced Tree: A balanced tree ensures O(log N) time for insertion and deletion. Two common examples of balanced trees are the Red-Black tree and the AVL tree. And the trees which are not balanced are called unbalanced trees.
Complete Binary Tree: It’s a binary tree where each level contains the maximum number of nodes that a level can have except the last layer, which is filled from left to right.

Example

Full Binary Tree: A full binary tree is a tree in which each node has either zero or two child nodes.

Example

Perfect Binary Tree: This is both complete and full.

Example

Difference between Stacks and Trees

Parameter	Stack	Tree
Structure	Linear data structure	Nonlinear data structure.
Notion	Top of the Stack.	The root of the node.
Data Accessibility	top() - Returns the top of the stack. push(x) - Insert value ‘x’ on top of the stack. pop() - Deletes top of the stack.	root->data - Represents data value of the node root. root->left - Represents pointer to left Node. root->right - Represents pointer to right node.
Insertion Complexity	O(1)	Depend on the type of tree. Best Case - O(log N) Worst Case - O(N)
Deletion Complexity	O(1)	Depends on the type of tree. Best Case - O(log N) Worst Case - O(N)
Find Minimum	O(N), without auxiliary space.	Depends on the type of tree. Best Case - O(log(N)) Worst Case - O(N)
Searching	O(N)	Depends on the type of tree. Best Case - O(log N) (in BST) Worst Case - O(N)
Implementation	Using an array and linked list.	It can be represented in an array or a user-defined struct or class.
Types	No types.	Many Types. E.g., BST, AVL Tree, ed Black tree, etc.
Applications	Backtracking, Memory Management (Recursion).	Fast insert, delete, search etc.

List of Top Stacks Questions

List of Top Trees Questions

Frequently Asked Questions(FAQs)

What type of data structures(Linear or Non-Linear) are Stacks and Trees?

Stack is a Linear Data Structure, while Tree is a Non-Linear Data structure.

What is the insertion complexity for a node in a binary tree and stack?

The insertion complexity of a binary tree in the worst case is O(n) where n is the number of nodes, whereas the insertion complexity of an element in stack is O(1) which is constant.

Conclusion

We’ve discussed what stack and tree data structures are and what’s the difference between them. Visit Coding Ninjas Studio to read more amazing blogs about data structures and algorithms.

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