“Top 100 Data Structures MCQs with Answers 2026”

 “Top 100 Data Structures MCQs with Answers 2026”

Prepare smarter with MCQ Journey’s Top 100 Data Structures MCQs with Answers 2026, designed for students, professionals, and competitive exam aspirants. This comprehensive collection of multiple-choice questions covers key topics in data structures including arrays, linked lists, stacks, queues, trees, graphs, and hashing. Each MCQ is carefully curated with detailed answers to help learners strengthen concepts, practice effectively, and boost exam confidence. Whether you are preparing for university exams, GATE, UPSC, SSC, banking exams, or technical interviews, these solved MCQs provide the perfect resource for revision and self-assessment. With a focus on exam preparation, practice questions, and competitive exams, MCQ Journey ensures you gain the edge needed to succeed. Updated for 2026, this set offers fresh, relevant content aligned with current exam trends. Explore, practice, and master data structures with these MCQs with answers — your trusted guide to success in computer science and engineering exams.

Q1. Which of the following is the correct way to declare an array in C? A. int arr[10]; B. arr int[10]; C. array arr[10]; D. int[10] arr; Answer: A

Q2. What is the time complexity of accessing an element in an array using its index? A. O(n) B. O(log n) C. O(1) D. O(n²) Answer: C

Q3. Which of the following is true about arrays? A. Arrays allow dynamic memory allocation. B. Arrays provide constant-time access using indices. C. Arrays are always faster than linked lists in insertion. D. Arrays cannot store primitive data types. Answer: B

Q4. In a singly linked list, each node contains: A. Data only B. Data and two pointers C. Data and one pointer D. Only a pointer Answer: C

Q5. Which data structure is used in function call management? A. Queue B. Stack C. Linked List D. Tree Answer: B

Q6. Which of the following is true about queues? A. Follows LIFO principle B. Follows FIFO principle C. Allows random access D. Stores elements in sorted order Answer: B

Q7. What is the height of a binary tree with only one node? A. -1 B. 0 C. 1 D. 2 Answer: B

Q8. Which traversal technique visits nodes in the order: Left, Root, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: B

Q9. Which algorithm is used to find the shortest path in a weighted graph? A. DFS B. BFS C. Dijkstra’s Algorithm D. Kruskal’s Algorithm Answer: C

Q10. What is the main advantage of hashing? A. Faster searching B. Reduced memory usage C. Easy sorting D. Sequential access Answer: A

Q11. In a singly linked list, each node contains: A. Data only B. Data and two pointers C. Data and one pointer D. Only a pointer Answer: C

Q12. What is the time complexity of inserting a node at the beginning of a linked list? A. O(n) B. O(1) C. O(log n) D. O(n²) Answer: B

Q13. Which of the following is true about doubly linked lists? A. Each node has one pointer. B. Each node has two pointers. C. Each node has three pointers. D. Each node has no pointers. Answer: B

Q14. Which data structure is used to implement recursion? A. Queue B. Stack C. Array D. Linked List Answer: B

Q15. Which operation is not possible in a stack? A. Push B. Pop C. Peek D. Random Access Answer: D

Q16. Which of the following is true about queues? A. Follows LIFO principle B. Follows FIFO principle C. Allows random access D. Stores elements in sorted order Answer: B

Q17. Which of the following is an application of queues? A. Function calls B. Job scheduling C. Binary search D. Depth-first search Answer: B

Q18. Which traversal technique visits nodes in the order: Root, Left, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: A

Q19. Which traversal technique visits nodes in the order: Left, Root, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: B

Q20. Which traversal technique visits nodes in the order: Left, Right, Root? A. Preorder B. Inorder C. Postorder D. Level Order Answer: C

Q21. Which data structure is used in Breadth First Search (BFS)? A. Stack B. Queue C. Linked List D. Tree Answer: B

Q22. Which data structure is used in Depth First Search (DFS)? A. Stack B. Queue C. Array D. Hash Table Answer: A

Q23. Which algorithm is used to find the shortest path in a weighted graph? A. DFS B. BFS C. Dijkstra’s Algorithm D. Kruskal’s Algorithm Answer: C

Q24. Which of the following is true about binary search trees (BST)? A. Left child > root B. Right child < root C. Left child < root, Right child > root D. No ordering Answer: C

Q25. What is the maximum number of nodes at level ‘l’ in a binary tree? A. 2^l B. l² C. l D. 2l Answer: A

Q26. Which of the following is true about hashing? A. Provides sequential access B. Provides constant-time search on average C. Always avoids collisions D. Requires sorted data Answer: B

Q27. Which of the following is a collision resolution technique? A. Binary Search B. Linear Probing C. Merge Sort D. Depth First Search Answer: B

Q28. Which of the following is true about graphs? A. Graphs contain only nodes. B. Graphs contain nodes and edges. C. Graphs contain only edges. D. Graphs contain arrays. Answer: B

Q29. Which of the following is true about adjacency matrix representation of graphs? A. Uses less memory for sparse graphs. B. Uses more memory for sparse graphs. C. Cannot represent weighted graphs. D. Cannot represent directed graphs. Answer: B

Q30. Which of the following is true about adjacency list representation of graphs? A. Uses more memory for sparse graphs. B. Uses less memory for sparse graphs. C. Cannot represent weighted graphs. D. Cannot represent directed graphs. Answer: B

Q31. Which operation is performed first in a stack? A. First In First Out B. Last In First Out C. Random Access D. Sequential Access Answer: B

Q32. Which of the following is true about stack overflow? A. Occurs when stack is empty B. Occurs when stack is full C. Occurs when queue is full D. Occurs when array is empty Answer: B

Q33. Which of the following is an application of stacks? A. Job scheduling B. Expression evaluation C. Breadth First Search D. Hashing Answer: B

Q34. Which of the following is true about circular queues? A. They use more memory than linear queues B. They avoid wastage of memory C. They cannot be implemented using arrays D. They cannot store more than one element Answer: B

Q35. What is the height of a binary tree with only one node? A. -1 B. 0 C. 1 D. 2 Answer: B

Q36. Which traversal technique visits nodes in the order: Root, Left, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: A

Q37. Which traversal technique visits nodes in the order: Left, Root, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: B

Q38. Which traversal technique visits nodes in the order: Left, Right, Root? A. Preorder B. Inorder C. Postorder D. Level Order Answer: C

Q39. Which traversal technique visits nodes level by level? A. Preorder B. Inorder C. Postorder D. Level Order Answer: D

Q40. Which of the following is true about binary search trees (BST)? A. Left child > root B. Right child < root C. Left child < root, Right child > root D. No ordering Answer: C

Q41. What is the maximum number of nodes at level ‘l’ in a binary tree? A. 2^l B. l² C. l D. 2l Answer: A

Q42. Which of the following is true about complete binary trees? A. All levels are completely filled except possibly the last B. All nodes have two children C. All nodes have one child D. No nodes have children Answer: A

Q43. Which of the following is true about graphs? A. Graphs contain only nodes B. Graphs contain nodes and edges C. Graphs contain only edges D. Graphs contain arrays Answer: B

Q44. Which of the following is true about adjacency matrix representation of graphs? A. Uses less memory for sparse graphs B. Uses more memory for sparse graphs C. Cannot represent weighted graphs D. Cannot represent directed graphs Answer: B

Q45. Which of the following is true about adjacency list representation of graphs? A. Uses more memory for sparse graphs B. Uses less memory for sparse graphs C. Cannot represent weighted graphs D. Cannot represent directed graphs Answer: B

Q46. Which data structure is used in Breadth First Search (BFS)? A. Stack B. Queue C. Linked List D. Tree Answer: B

Q47. Which data structure is used in Depth First Search (DFS)? A. Stack B. Queue C. Array D. Hash Table Answer: A

Q48. Which algorithm is used to find the shortest path in a weighted graph? A. DFS B. BFS C. Dijkstra’s Algorithm D. Kruskal’s Algorithm Answer: C

Q49. Which of the following is true about spanning trees? A. Contains cycles B. Contains all nodes with minimum edges C. Contains only one node D. Contains no edges Answer: B

Q50. Which algorithm is used to find the minimum spanning tree? A. Dijkstra’s Algorithm B. Kruskal’s Algorithm C. BFS D. DFS Answer: B

Q51. Which of the following is true about BFS? A. Uses stack B. Uses queue C. Uses recursion D. Uses priority queue Answer: B

Q52. Which of the following is true about DFS? A. Uses stack B. Uses queue C. Uses array D. Uses hash table Answer: A

Q53. Which algorithm is used to find the shortest path in a weighted graph? A. DFS B. BFS C. Dijkstra’s Algorithm D. Kruskal’s Algorithm Answer: C

Q54. Which algorithm is used to find the minimum spanning tree? A. Dijkstra’s Algorithm B. Kruskal’s Algorithm C. BFS D. DFS Answer: B

Q55. Which of the following is true about spanning trees? A. Contains cycles B. Contains all nodes with minimum edges C. Contains only one node D. Contains no edges Answer: B

Q56. Which of the following is true about complete binary trees? A. All levels are completely filled except possibly the last B. All nodes have two children C. All nodes have one child D. No nodes have children Answer: A

Q57. Which of the following is true about binary search trees (BST)? A. Left child > root B. Right child < root C. Left child < root, Right child > root D. No ordering Answer: C

Q58. Which traversal technique visits nodes level by level? A. Preorder B. Inorder C. Postorder D. Level Order Answer: D

Q59. Which traversal technique visits nodes in the order: Root, Left, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: A

Q60. Which traversal technique visits nodes in the order: Left, Root, Right? A. Preorder B. Inorder C. Postorder D. Level Order Answer: B

Q61. Which traversal technique visits nodes in the order: Left, Right, Root? A. Preorder B. Inorder C. Postorder D. Level Order Answer: C

Q62. Which of the following is true about hashing? A. Provides sequential access B. Provides constant-time search on average C. Always avoids collisions D. Requires sorted data Answer: B

Q63. Which of the following is a collision resolution technique? A. Binary Search B. Linear Probing C. Merge Sort D. Depth First Search Answer: B

Q64. Which of the following is true about adjacency matrix representation of graphs? A. Uses less memory for sparse graphs B. Uses more memory for sparse graphs C. Cannot represent weighted graphs D. Cannot represent directed graphs Answer: B

Q65. Which of the following is true about adjacency list representation of graphs? A. Uses more memory for sparse graphs B. Uses less memory for sparse graphs C. Cannot represent weighted graphs D. Cannot represent directed graphs Answer: B

Q66. Which of the following is true about graphs? A. Graphs contain only nodes B. Graphs contain nodes and edges C. Graphs contain only edges D. Graphs contain arrays Answer: B

Q67. Which of the following is true about directed graphs? A. Edges have no direction B. Edges have direction C. Cannot represent weighted graphs D. Cannot represent nodes Answer: B

Q68. Which of the following is true about weighted graphs? A. Edges have weights B. Nodes have weights C. Cannot represent direction D. Cannot represent adjacency Answer: A

Q69. Which of the following is true about unweighted graphs? A. Edges have no weights B. Nodes have weights C. Cannot represent direction D. Cannot represent adjacency Answer: A

Q70. Which of the following is true about trees? A. Trees contain cycles B. Trees contain nodes and edges without cycles C. Trees contain only nodes D. Trees contain only edges Answer: B

Q71. Which of the following is a common collision resolution technique in hashing? A. Binary Search B. Linear Probing C. Merge Sort D. Depth First Search Answer: B

Q72. Which of the following is true about open addressing in hashing? A. Stores multiple elements in one bucket B. Resolves collisions by finding another empty slot C. Requires linked lists D. Cannot handle collisions Answer: B

Q73. Which of the following is true about chaining in hashing? A. Uses arrays only B. Uses linked lists to store multiple elements in one bucket C. Cannot resolve collisions D. Requires sorting Answer: B

Q74. Which of the following is true about load factor in hashing? A. Ratio of number of elements to table size B. Ratio of table size to number of elements C. Ratio of collisions to table size D. Ratio of collisions to elements Answer: A

Q75. Which traversal technique is used in Depth First Search (DFS)? A. Level Order B. Preorder C. Breadth First D. Random Order Answer: B

Q76. Which traversal technique is used in Breadth First Search (BFS)? A. Level Order B. Preorder C. Postorder D. Random Order Answer: A

Q77. Which of the following is true about dynamic programming? A. Solves problems using recursion only B. Stores solutions to subproblems to avoid recomputation C. Always faster than greedy algorithms D. Cannot be applied to optimization problems Answer: B

Q78. Which of the following is true about greedy algorithms? A. Always optimal B. Makes locally optimal choices C. Stores subproblem solutions D. Requires recursion Answer: B

Q79. Which of the following is true about divide and conquer algorithms? A. Breaks problems into subproblems and combines solutions B. Stores subproblem solutions C. Makes locally optimal choices D. Requires hashing Answer: A

Q80. Which of the following is true about recursion? A. Function calls itself B. Function calls another function only C. Cannot solve problems D. Requires hashing Answer: A

Q81. Which of the following is true about memoization? A. Stores solutions to subproblems B. Makes locally optimal choices C. Breaks problems into subproblems D. Requires hashing Answer: A

Q82. Which of the following is true about AVL trees? A. Self-balancing binary search tree B. Non-balancing binary search tree C. Cannot store data D. Requires hashing Answer: A

Q83. Which of the following is true about B-trees? A. Used in databases B. Cannot store data C. Requires hashing D. Stores only one element Answer: A

Q84. Which of the following is true about heaps? A. Complete binary tree B. Cannot store data C. Requires hashing D. Stores only one element Answer: A

Q85. Which of the following is true about priority queues? A. Implemented using heaps B. Cannot store data C. Requires hashing D. Stores only one element Answer: A

Q86. Which of the following is true about Kruskal’s Algorithm? A. Finds shortest path B. Finds minimum spanning tree C. Finds maximum flow D. Finds maximum matching Answer: B

Q87. Which of the following is true about Prim’s Algorithm? A. Finds shortest path B. Finds minimum spanning tree C. Finds maximum flow D. Finds maximum matching Answer: B

Q88. Which of the following is true about Bellman-Ford Algorithm? A. Finds shortest path with negative weights B. Finds minimum spanning tree C. Finds maximum flow D. Finds maximum matching Answer: A

Q89. Which of the following is true about Floyd-Warshall Algorithm? A. Finds all pairs shortest path B. Finds minimum spanning tree C. Finds maximum flow D. Finds maximum matching Answer: A

Q90. Which of the following is true about dynamic arrays? A. Can grow or shrink in size B. Cannot store data C. Requires hashing D. Stores only one element Answer: A

Q91. Which of the following is true about linked lists? A. Allow dynamic memory allocation B. Cannot store data C. Require hashing D. Store only one element Answer: A

Q92. Which of the following is true about stacks? A. Follow LIFO principle B. Follow FIFO principle C. Allow random access D. Store elements in sorted order Answer: A

Q93. Which of the following is true about queues? A. Follow LIFO principle B. Follow FIFO principle C. Allow random access D. Store elements in sorted order Answer: B

Q94. Which of the following is true about circular queues? A. Avoid wastage of memory B. Cannot store data C. Require hashing D. Store only one element Answer: A

Q95. Which of the following is true about double-ended queues (deque)? A. Allow insertion and deletion at both ends B. Cannot store data C. Require hashing D. Store only one element Answer: A

Q96. Which of the following is true about graphs? A. Contain nodes and edges B. Contain only nodes C. Contain only edges D. Contain arrays Answer: A

Q97. Which of the following is true about directed graphs? A. Edges have direction B. Edges have no direction C. Cannot represent weighted graphs D. Cannot represent nodes Answer: A

Q98. Which of the following is true about weighted graphs? A. Edges have weights B. Nodes have weights C. Cannot represent direction D. Cannot represent adjacency Answer: A

Q99. Which of the following is true about unweighted graphs? A. Edges have no weights B. Nodes have weights C. Cannot represent direction D. Cannot represent adjacency Answer: A

Q100. Which of the following is true about trees? A. Contain nodes and edges without cycles B. Contain cycles C. Contain only nodes D. Contain only edges Answer: A

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