Thread by @swapnakpanda

Data Structures and Algorithms (DSA)

🔥 Frequently Asked Interview Questions 🔥

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I am soon going to start my blog. All the questions featured here will be answered in detail over there. I will post answers for some of these in Twitter platform as well. Questions will be added with time. Stay tuned.

Now, let's go through the questions.

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1️⃣ Basics

✪ What is an algorithm?
✪ What is time complexity?
✪ What is space complexity?
✪ What is a Data Structure?
✪ What are types of Data Structures? (Linear/Non-linear)
✪ What are different operations that can be performed on different data structures?

2️⃣ Array/Stack/Queue/HashTable

✪ Write pseudo code for Array based operations
✪ Write pseudo code for Stack based operations
✪ Write pseudo code for Queue based operations
✪ Implement a Stack using Queue
✪ Implement a Queue using a Stack
✪ What is a dynamic sized array

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✪ What is an associative array?
✪ What data structure should be used for LRU cache?
✪ Write a code to reverse an array
✪ Write a code to sort an array
✪ What is a Hash Table?
✪ What are Keys and Values in a Hash Table?
✪ What is a Hashing Function?

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✪ What are different Hashing Functions available?
✪ What is a hash collision?
✪ What are different techniques used to avoid/resolve a hash collision?
✪ How is a Stack different from a Queue?
✪ What is a Dequeue?
✪ What is a Priority Queue?

3️⃣ Linked List

✪ What are various types of linked list?
✪ How is an Array different from a Linked List?
✪ For which use cases Linked List should be preferred?
✪ Write pseudo code to insert/delete/fetch a node in a Linked List

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✪ Write pseudo code to insert/delete/fetch a node in a Doubly Linked List
✪ How to detect if a cycle (loop) is formed in a linked list?
✪ Reverse a linked list
✪ Retrieve the middle element in a Linked List
✪ Retrieve nth node from the end in a Linked List

4️⃣ Tree

✪ What is a Tree?
✪ What is a Binary Tree?
✪ What is a Binary Search Tree?
✪ What is a Heap?
✪ What is an AVL Tree?
✪ What is a B-Tree?
✪ What is a B+ Tree?
✪ What is a Red Black Tree?
✪ What is a Trie?
✪ How to find height of a binary tree?

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✪ What is depth of a node?
✪ What is degree of a node?
✪ What is In-Order, Pre-Order and Post-Order Traversals?
✪ Convert a Double Linked List to a Binary Tree
✪ Convert a Binary Tree to a Double Linked List
✪ How to check if a Binary Tree is Binary Search Tree?

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✪ What is a Heap?
✪ What is a Max Heap and, Min Heap?
✪ What is Heapify operation?
✪ How to pick a max/min element from a Heap?
✪ How to extract a max/min element from a Heap?
✪ What is the difference between pick and extract?
✪ What is a Fibonacci Heap?

5️⃣ Graphs

✪ What data structures are used to represent a graph?
✪ How is a Graph different from a Tree?
✪ What is BFS and DFS?
✪ Which data structures is used for BFS and DFS?
✪ What is Minimum Spanning Tree
✪ What is Kruskal's algorithm?
✪ What is Prim's algorithm?

6️⃣ Sorting/Searching

✪ Explain Best Case, Worst Case and Average Case Time Complexities of various sorting algorithms
✪ What is the worst case for Merge Sort?
✪ What is the worst case for Quick Sort?
✪ What are different searching algorithms available?

7️⃣ Algorithms

✪ What is recursion?
✪ What is divide and conquer? Give some example.
✪ What is a greedy algorithm? Why is it used?
✪ Mention some greedy algorithm.