100 Most Asked DSA Interview Questions

Hello and welcome to Codipher.com. Today in this article i am going to provide you a list of DSA Interview Questions that are asked in every data structures and algorithm Interview. Before we dive in i want you to know that if you need answers of below DSA Interview Questions then at the last of this article i have provided a list of links where you can easily find the answers. So without wasting further time let’s dive in.

• Basic DSA Interview Questions

1. What is an algorithm?

2. What is time complexity?

3. What is space complexity?

4. What is a Data Structure?

5. What is difference between file structure and storage structure?

6. Differentiate NULL and VOID?

7. Do dynamic memory allocations help in managing data? How?

8. Explain the max heap data structure?

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• Basic Array / Stack / Queue / HashTable

1. Write pseudo code for Array based operations?

2. Write pseudo code for stack based operations?

3. Write pseudo code for Queue based operations?

4. Implement a stack using queue?

5. Implement a queue using a stack?

6. What is a dynamic sized array?

7. What is an associative array?

8. What is a Dequeue and some advantages?

9. Explain the jagged array?

• Graphs DSA Interview Questions

1. What is minimum spanning tree?

2. What is Kruskal’s algorithm?

3. What is Prim’s algorithm?

4. What is BFS and DFS?

5. What data structures are used to represent a graph?

6. How is a graph different from a tree?

7. What are the applications of graph data structure?

• Sorting / Searching

1. What is the worst case for merge sort?

2. What is the worst case for quick sort?

3. What are different searching Algo available?

4. Explain best case, worst case and average?

5. Case time complexities of various sorting algorithms?

6. What is the merge sort and how does it work?

7. How does the selection sort work?

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• Algorithms Interview Questions

1. What is recursion?

2. What is divide and conquer? Give some examples?

3. What is a greedy algorithm? Why is it used?

4. Mention some greedy algorithms?

• Advance Array DSA Interview Questions

1. How do you find the missing number in a given integer array of 1 to 100?

2. How do you find the duplicate number on a given integer array?

3. How do you find the largest and smallest number in an unsorted integer array?

4. How do you find all pairs of an integer array whose sum is equal to a given number?

5. How do you find duplicate numbers in an array if it contains multiple duplicates?

6. How are duplicates removed from a given array in Java?

7. How is an integer array sorted in place using the quicksort algorithm?

8. How do you remove duplicates from an array in place?

9. How do you reverse an array in place in Java?

10. How are duplicates removed from an array without using any library?

11. How do you reference all of the elements in a one-dimension array?

• Linked List DSA Interview Questions

1. How do you find the middle elementvof a singly linked list in one pass?

2. How do you check if a given linked list contains a cycle? How do you find the starting node of the cycle?

3. How do you reverse a linked list?

4. How do you reverse a singly linked list without recursion?

5. How are duplicate nodes removed in an unsorted linked list?

6. How do you find the length of singly linked list?

7. How do you find the third node from the end in a singly linked list?

8. How do you find the sum of two linked lists using stack?

9. What are various types of linked list?

10. How is array different from a linked list?

11. For which use cases linked list should be preferred?

12. Reverse a linked list?

13. Are linked lists considered linear or non-linear data structures?

14. Name the ways to determine whether a linked list has a loop?

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• Binary Tree DSA Interview Questions

1. How is a binary search tree implemented?

2. How do you perform preorder traversel in a given binary tree?

3. How do you traverse a given binary tree in preorder without recursion?

4. How do you perform an inorder traversel in a given binary tree?

5. How do you print all nodes of given binary tree using inorder traversel without recursion?

6. How do you implement a postorder traversel algorithm?

7. How do you traverse a binary tree in postorder traversel without recursion?

8. How are all leaves of binary search tree printed?

9. How do you count a number of leaf nodes in a given binary tree?

10. How do you performba binary search in a given array?

11. What is a tree?

12. What is a binary tree?

13. What is a binary search tree?

14. What is a Heap?

15. What is an AVL Tree?

16. What is a B- tree?

17. What is a B+ tree?

18. What is a red black tree?

• String

1. How do you print duplicate characters from a string?

2. How do you check if two strings are anagrams of each other?

3. How do you print the first non-repeated character from a string?

4. How can a given string be reversed using recursion?

5. How do you check if a string contains only digits?

6. How are duplicate characters found in a string?

7. How do you count a number of vowels and constants in a given string?

8. How do you count the occurrence of a given character in a string?

9. How do find all permutations of a string?

10. How do you reverse words in given sentence without using any library method?

11. How do you check if two strings are rotation of each other?

12. How do you check if a given string is a palindrome?

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• Miscellaneous DSA Interview Questions

1. How is a bubble sort algorithm implemented?

2. How is an iterative quicksort algorithm implemented?

3. How do you implement an insertion sort algorithm?

4. How do you implement a bucket sort algorithm?

5. How is a merge sort algorithm implemented?

6. How do you implement a counting sort algorithm?

7. How is a radix sort algorithm implemented?

8. Hwo do you swap two numbers without using the third variable?

9. How do you check if two rectangles overlap with each other?

10. How do you design a vending machine?

That’s it for this article guys, these are the most important DSA Interview Questions. If you found this article helpful don’t forget to leave a comment below.

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• DSA Interview Questions with Answers

• Tutorialspoint
• GeeksForGeeks
• Javatpoint
• InterviewBit