Matrix – Interview Questions and Practice Problems

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

1. Print matrix in spiral orderMedium
2. Create a spiral matrix from a given arrayMedium
3. Shift all matrix elements by 1 in spiral orderMedium
4. Change all elements of row i and column j in a matrix to 0 if cell (i, j) is 0Medium
5. Print diagonal elements of a matrix having a positive slopeMedium
6. Replace all occurrences of 0 that are not surrounded by 1 in a binary matrixMedium
7. In-place rotate matrix by 90 degrees in a clockwise directionEasy
8. Count negative elements present in the sorted matrix in linear timeEasy
9. Report all occurrences of an element in a row-wise and column-wise sorted matrix in linear timeMedium
10. Check if a matrix is a Toeplitz or notEasy
11. In-place rotate matrix by 180 degreesMedium
12. Fill binary matrix with alternating rectangles of 0 and 1Medium
13. Find all common elements present in each row of a matrixMedium
14. Find common elements present in all rows of a matrixMedium
15. Find the index of a row containing the maximum number of 1’s in a binary matrixHard
16. Find the largest square submatrix which is surrounded by all 1’sMedium
17. Print a spiral square matrix without using any extra spaceHard
18. Young Tableau | Insert, Search, Extract-Min, Delete, ReplaceHard
19. Replace all occurrences of 0 that are surrounded by 1 in a binary matrixMedium
20. Find the area of the largest rectangle of 1’s in a binary matrixHard
21. Find maximum value of M[c][d] – M[a][b] over all choices of indexesMedium
22. Sort an array using Young tableauHard
23. Print all possible solutions to N–Queens problemHard
24. Print all possible Knight’s tours on a chessboardHard
25. Find the shortest path in a mazeMedium
26. Find the longest possible route in a matrixMedium
27. Find the path from source to destination in a matrix that satisfies given constraintsMedium
28. Find the total number of unique paths in a maze from source to destinationMedium
29. Magnet PuzzleHard
30. Find all paths from the first cell to the last cell of a matrixMedium
31. Print all shortest routes in a rectangular gridMedium
32. Find the shortest route in a device to construct a given stringMedium
33. Find all occurrences of the given string in a character matrixHard
34. Construct an ancestor matrix from a binary treeEasy
35. Construct a binary tree from an ancestor matrixHard
36. Find the size of the largest square submatrix of 1’s present in a binary matrixMedium
37. Matrix Chain Multiplication using Dynamic ProgrammingHard
38. Find minimum cost to reach the last cell of a matrix from its first cellMedium
39. Find the longest sequence formed by adjacent numbers in the matrixMedium
40. Count the number of paths in a matrix with a given cost to reach the destination cellMedium
41. Collect maximum points in a matrix by satisfying given constraintsHard
42. Find the number of ways to fill an N × 4 matrix with 1 × 4 tilesMedium
43. Ways to reach the bottom-right corner of a matrix with exactly k turns allowedHard
44. Calculate the minimum cost to reach the destination city from the source cityMedium
45. Find the probability that a person is alive after taking n steps on an islandMedium
46. Maximum Length Snake SequenceMedium
47. Calculate the size of the largest plus of 1’s in a binary matrixHard
48. Count all paths in a matrix from the first cell to the last cellEasy
49. Calculate the sum of all elements in a submatrix in constant timeMedium
50. Find maximum sum K × K submatrix in a given M × N matrixHard
51. Find maximum sum submatrix present in a matrixMedium
52. Find the length of the longest path in a matrix with consecutive charactersMedium
53. Collect maximum value of coins in a matrixHard
54. Transitive closure of a graphEasy
55. All-Pairs Shortest Paths – Floyd Warshall AlgorithmEasy
56. Determine a negative-weight cycle in a graphMedium
57. Merge M sorted lists each containing N elementsHard
58. Chess Knight Problem | Find the shortest path from source to destinationHard
59. Shortest path in a maze – Lee AlgorithmMedium
60. Find the shortest safe route in a field with sensors presentHard
61. Flood Fill AlgorithmMedium
62. Count number of islandsMedium
63. Find the shortest path from source to destination in a matrix that satisfies given constraintsHard
64. Find minimum passes required to convert all negative values in a matrixHard
65. Find the shortest distance of every cell from a landmine inside a mazeHard
66. Find duplicate rows in a binary matrixMedium
67. Generate a list of possible words from a character matrixHard