🚀 Coding Interview Questions with Answers (Part 8)

7️⃣1️⃣ What is a Sparse Matrix?

Answer:

A sparse matrix is a matrix in which most of the elements are 0. Instead of storing every element, only the non-zero elements are stored to save memory.

Applications:

• Machine Learning

• Graph representations

• Scientific computing

• Image processing

Advantages:

• Saves memory

• Improves computational efficiency

7️⃣2️⃣ What is a Dynamic Array?

Answer:

A dynamic array is an array that can automatically resize itself when more elements are added.

Unlike a fixed-size array, it allocates additional memory when its capacity is reached.

Examples:

• ArrayList in Java

• vector in C++

• list (dynamic array implementation) in Python

Advantages:

• Flexible size

• Fast random access

• Easy insertion at the end

7️⃣3️⃣ What is Load Factor?

Answer:

Load factor is the ratio of the number of stored elements to the total number of buckets in a hash table.

Formula:

Load Factor = Number of Elements / Number of Buckets

A high load factor increases the likelihood of collisions, while a low load factor improves performance but uses more memory.

7️⃣4️⃣ What is Collision Resolution?

Answer:

Collision resolution refers to the techniques used to handle situations where multiple keys are mapped to the same location in a hash table.

Common Methods:

• Separate Chaining

• Linear Probing

• Quadratic Probing

• Double Hashing

The goal is to maintain efficient search, insertion, and deletion operations.

7️⃣5️⃣ What is the Difference Between Linear Probing and Chaining?

Answer:

Linear Probing

• Stores collided elements in the next available slot.

• Uses open addressing.

• Requires less memory.

• Performance decreases as the table becomes full.

Separate Chaining

• Stores collided elements in a linked list at the same bucket.

• Easier to handle many collisions.

• Requires additional memory for linked lists.

7️⃣6️⃣ What is Tree Traversal?

Answer:

Tree traversal is the process of visiting every node in a tree exactly once in a specific order.

Common Types:

• Preorder

• Inorder

• Postorder

• Level-order

Tree traversal is used for searching, printing, and processing tree data.

7️⃣7️⃣ What is the Difference Between Preorder, Inorder, and Postorder Traversal?

Answer:

• Preorder: Root → Left → Right

• Inorder: Left → Root → Right

• Postorder: Left → Right → Root

Applications:

• Preorder: Copying a tree

• Inorder: Produces sorted output in a Binary Search Tree

• Postorder: Deleting or freeing a tree

7️⃣8️⃣ What is Level-Order Traversal?

Answer:

Level-order traversal visits the nodes of a tree level by level, starting from the root.

It uses a Queue and is also known as Breadth-First Traversal (BFS) for trees.

Applications:

• Printing trees level by level

• Finding the shortest path in unweighted trees

• Binary tree serialization

7️⃣9️⃣ What is the Recursion Stack?

Answer:

The recursion stack is the memory area used by the system to keep track of active recursive function calls.