Sorting – Interview Questions and Practice Problems

In this post, we have listed out commonly asked interview questions that use sorting:

1. Insertion Sort AlgorithmEasy
2. Selection Sort AlgorithmEasy
3. Bubble Sort AlgorithmEasy
4. Merge Sort AlgorithmEasy
5. Iterative Merge Sort Algorithm (Bottom-up Merge Sort)Medium
6. Quicksort AlgorithmMedium
7. Hybrid QuickSort AlgorithmMedium
8. Quicksort using Dutch National Flag AlgorithmMedium
9. Quicksort algorithm using Hoare’s partitioning schemeMedium
10. Counting Sort AlgorithmEasy
11. In-place vs out-of-place algorithmsBeginner
12. Heap Sort AlgorithmMedium
13. Introsort Algorithm – Overview and C++ ImplementationHard
14. External Merge Sort AlgorithmHard
15. Merge two sorted linked lists from their endMedium
16. Merge sort algorithm for a singly linked listHard
17. Sort a doubly-linked list using merge sortMedium
18. Inversion count of an arrayHard
19. Problems solved using partitioning logic of QuicksortEasy
20. How to Boost QuickSort Performance?Easy
21. Sort elements by their frequency and indexMedium
22. Sort an array based on order defined by another arrayMedium
23. Efficiently sort an array with many duplicated valuesMedium
24. Find the largest number possible from a given set of numbersMedium
25. Find surpasser count for each array elementHard
26. Segregate positive and negative integers using merge sortMedium
27. Find a pair with the given sum in an arrayEasy
28. Find the maximum product of two integers in an arrayEasy
29. Sort an array of 0’s, 1’s, and 2’s (Dutch National Flag Problem)Medium
30. In-place merge two sorted arraysMedium
31. Merge two arrays by satisfying given constraintsMedium
32. Find all distinct combinations of a given length – IMedium
33. Find the smallest window in an array sorting which will make the entire array sortedMedium
34. Find minimum platforms needed to avoid delay in the train arrivalMedium
35. Sort an array in one swap whose two elements are swappedEasy
36. Find a triplet with the given sum in an arrayMedium
37. Find pairs with difference k in an arrayEasy
38. 4–Sum Problem | Quadruplets with a given sumMedium
39. Print all quadruplets with a given sum | 4 sum problem extendedMedium
40. Find two numbers with maximum sum formed by array digitsEasy
41. Find a triplet having the maximum product in an arrayMedium
42. Find a pair with a minimum absolute sum in an arrayEasy
43. Find minimum product among all combinations of triplets in an arrayMedium
44. Find all distinct combinations of a given length – IIMedium
45. Activity Selection ProblemEasy
46. Job Sequencing Problem with DeadlinesMedium
47. Water Jugs ProblemHard
48. Sort an array using Young tableauHard
49. Find all distinct combinations of a given length with repetition allowedMedium
50. Print all triplets in an array with a sum less than or equal to a given numberMedium
51. Group anagrams together from a list of wordsMedium
52. Find minimum operations required to transform a string into another stringHard
53. Find all palindromic permutations of a stringMedium
54. Iterative approach to finding permutations of a stringHard
55. Find all lexicographically next permutations of a string sorted in ascending orderHard
56. Find all lexicographic permutations of a stringHard
57. Print all distinct subsets of a given setHard
58. Merging Overlapping IntervalsMedium
59. Maximum Overlapping Intervals ProblemMedium
60. Iterative Implementation of QuicksortMedium
61. Construct a balanced BST from the given keysEasy
62. Find the odd occurring element in an array in logarithmic timeMedium
63. Find pairs with difference k in an array | Constant Space SolutionMedium
64. Weighted Interval Scheduling ProblemMedium
65. Box Stacking ProblemHard
66. Activity Selection Problem using Dynamic ProgrammingMedium
67. Weighted Interval Scheduling – Dynamic Programming SolutionMedium
68. Longest Increasing Subsequence using LCSMedium
69. Kruskal’s Algorithm for finding Minimum Spanning TreeHard
70. Merge M sorted lists of variable lengthHard
71. Merge M sorted lists each containing N elementsHard
72. Lexicographic sorting of a given set of keysMedium