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Top 72 Data Structures & Algorithms Interview Questions & Answers (2026)
72 Questions
33 Beginner
24 Intermediate
15 Advanced
About Data Structures & Algorithms
This technology is widely used in software development and is a frequent topic in technical interviews at companies of all sizes.
What to Expect in a Data Structures & Algorithms Interview
Interviews cover both foundational concepts and practical application of this technology, with questions ranging from definitions to architectural decision-making.
How to Use This Guide
Work through questions in order of difficulty to build your understanding progressively. Bookmark challenging questions and revisit them before your interview.
Curated by Tech Baithak Editorial Team · Last updated: May 2026
Beginner
33 questions
Core concepts every Data Structures & Algorithms developer must know.
01
What is a data structure?
02
What is an array?
03
What is a linked list?
04
What is a stack?
05
What is a queue?
06
What is Big O notation?
07
What is binary search?
08
What is bubble sort?
09
What is selection sort?
10
What is insertion sort?
11
What is merge sort?
12
What is quicksort?
13
What is a hash table / hash map?
14
What is a binary tree?
15
What is a binary search tree (BST)?
16
What are tree traversal methods?
17
What is a heap?
18
What is a graph?
19
What is Breadth-First Search (BFS)?
20
What is Depth-First Search (DFS)?
21
What is recursion?
22
What is dynamic programming?
23
What is a trie (prefix tree)?
24
What is a set and how is it different from a list?
25
What is the two-pointer technique?
26
What is the sliding window technique?
27
What is a priority queue?
28
What is the difference between a stack and a queue?
29
What is a circular linked list?
30
What is Floyd's cycle detection algorithm?
31
What is a deque (double-ended queue)?
32
What is heapsort?
33
What is the difference between depth and height of a tree?
Intermediate
24 questions
Practical knowledge for developers with hands-on experience.
01
What is the Knapsack problem?
02
What is the Longest Common Subsequence (LCS)?
03
What is topological sorting?
04
What is Dijkstra's algorithm?
05
What is Bellman-Ford algorithm?
06
What is Floyd-Warshall algorithm?
07
What is a minimum spanning tree (MST)?
08
What is Union-Find (Disjoint Set Union)?
09
What is the longest increasing subsequence (LIS)?
10
What is a segment tree?
11
What is a Fenwick tree (Binary Indexed Tree)?
12
What is a balanced binary search tree (AVL tree)?
13
What is a Red-Black tree?
14
What is the edit distance (Levenshtein distance) problem?
15
What is the coin change problem?
16
What is memoization vs tabulation in dynamic programming?
17
What is the activity selection / interval scheduling problem?
18
What is the sliding window maximum problem?
19
What is a monotonic stack and its applications?
20
What is the subset sum problem?
21
What is a graph coloring problem?
22
What is the N-Queens problem?
23
What is Kadane's algorithm?
24
What is a balanced parentheses problem and how to solve it?
Advanced
15 questions
Deep expertise questions for senior and lead roles.
01
What is amortized analysis?
02
What is the A* pathfinding algorithm?
03
What is Tarjan's algorithm for finding Strongly Connected Components?
04
What is the Master Theorem for solving recurrences?
05
What are NP, NP-Complete, and NP-Hard problems?
06
What is the Boyer-Moore voting algorithm?
07
What is the Rabin-Karp string matching algorithm?
08
What is the KMP (Knuth-Morris-Pratt) algorithm?
09
What is a B-tree and where is it used?
10
What is the difference between DFS and BFS in terms of space complexity?
11
What is the travelling salesman problem (TSP)?
12
What is the difference between greedy algorithms and dynamic programming?
13
What is Huffman encoding?
14
What is the difference between DFS recursive and iterative implementations and their implications?
15
What is matrix exponentiation and when is it used?
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72 questions total