Queue Data Structure: Practice Problems and Interview Questions

Queue Data Structure

A Queue is a linear First-In-First-Out (FIFO) data structure which means that the first element added to the queue will be the first one to be removed. Therefore, once a new element is added to the queue, all elements that were added before have to be removed before the new element can be removed.

In this post, we have listed out commonly asked interview questions that use queue data structure:

1. Queue implementation using an array — C, C++, Java, Python
2. Queue Implementation using a Linked List
3. Implement a stack using the queue data structure
4. Implement a queue using the stack data structure
5. Efficiently print all nodes between two given levels in a binary tree
6. Chess Knight Problem | Find the shortest path from source to destination
7. Shortest path in a maze — Lee Algorithm
8. Find the shortest safe route in a field with sensors present
9. Flood Fill Algorithm
10. Count number of islands
11. Find the shortest path from source to destination in a matrix that satisfies given constraints
12. Generate binary numbers between 1 to `n` using a queue
13. Calculate the height of a binary tree
14. Delete a binary tree
15. Level order traversal of a binary tree
16. Spiral order traversal of a binary tree
17. Reverse level order traversal of a binary tree
18. Print all nodes of a perfect binary tree in a specific order
19. Print left view of a binary tree
20. Find the next node at the same level as the given node in a binary tree
21. Check if a binary tree is a complete binary tree or not
22. Print diagonal traversal of a binary tree
23. Print corner nodes of every level in a binary tree
24. Invert Binary Tree
25. Find minimum passes required to convert all negative values in a matrix
26. Convert a binary tree into a doubly-linked list in spiral order
27. Check if a binary tree is a min-heap or not
28. Invert alternate levels of a perfect binary tree
29. Convert a Binary Search Tree into a Min Heap
30. Snake and Ladder Problem
31. Find the shortest distance of every cell from a landmine inside a maze
32. Convert a multilevel linked list to a singly linked list
33. Check if an undirected graph contains a cycle or not
34. Find maximum cost path in a graph from a given source to a given destination
35. Total paths in a digraph from a given source to a destination having exactly `m` edges
36. Least cost path in a digraph from a given source to a destination having exactly `m` edges
37. Breadth-First Search (BFS)
38. Traverse a given directory using BFS and DFS in Java
39. Perform vertical traversal of a binary tree
40. Compute the maximum number of nodes at any level in a binary tree
41. Print right view of a binary tree
42. Find the minimum depth of a binary tree
43. Depth-First Search (DFS) vs Breadth-First Search (BFS)
44. Bipartite Graph
45. Compute the least cost path in a weighted digraph using BFS
46. Find the path between given vertices in a directed graph
47. Construct a directed graph from an undirected graph that satisfies given constraints
48. Print nodes of a binary tree in vertical order

Thanks for reading.