Matrix are a fundamental data structure with vast applications in computer science. This article will explore a variety of coding problems that uses the matrix data structure. Through these hands-on exercises, readers will develop practical skills in matrix manipulation and algorithm implementation. From basic operations to more advanced matrix-based techniques, this collection of problems aims to build the reader’s expertise in working with this powerful data structure.

Practice Problems on the Matrix Data Structure:

• Rotate Matrix Elements
• Inplace rotate square matrix by 90 degrees | Set 1
• Rotate a matrix by 90 degree without using any extra space | Set 2
• Rotate a Matrix by 180 degree
• Rotate each ring of matrix anticlockwise by K elements
• Turn an image by 90 degree
• Check if all rows of a matrix are circular rotations of each other
• Sort the given matrix
• Find the row with maximum number of 1s
• Find median in row wise sorted matrix
• Matrix Multiplication | Recursive
• Program to multiply two matrices
• Program for scalar multiplication of a matrix
• Program to print Lower triangular and Upper triangular matrix of an array
• Find distinct elements common to all rows of a matrix
• Print a given matrix in spiral form
• Find maximum element of each row in a matrix
• Find unique elements in a matrix
• Shift matrix elements row-wise by k
• Different Operations on Matrices
• Print a given matrix in counter-clock wise spiral form
• Swap major and minor diagonals of a square matrix
• Maximum path sum in matrix
• Squares of Matrix Diagonal Elements
• Move matrix elements in given direction and add elements with same value
• Sorting rows of matrix in ascending order followed by columns in descending order
• Sum of middle row and column in Matrix
• Row-wise vs column-wise traversal of matrix
• Rotate the matrix right by K times
• Program to check idempotent matrix
• Program to check Involutory Matrix
• Interchange elements of first and last rows in matrix
• Print matrix in zag-zag fashion
• Row wise sorting in 2D array
• Program for Markov matrix
• Program to check diagonal matrix and scalar matrix
• Sort the matrix row-wise and column-wise
• Find the number of islands
• Magic Square | Even Order
• Magic Square
• Check given matrix is magic square or not
• Check given matrix is magic square or not
• Kronecker Product of two matrices
• Count sub-matrices having sum divisible ‘k’
• Diagonally Dominant Matrix
• Minimum operations required to make each row and column of matrix equals
• Count frequency of k in a matrix of size n where matrix(i, j) = i+j
• Given 1’s, 2’s, 3’s ……k’s print them in zig zag way.
• Number of cells a queen can move with obstacles on the chessborad
• Maximum product of 4 adjacent elements in matrix
• Minimum flip required to make Binary Matrix symmetric
• Program to check if matrix is lower triangular
• Program to check if matrix is upper triangular
• Frequencies of even and odd numbers in a matrix
• Center element of matrix equals sums of half diagonals
• Program for Identity Matrix
• Program to swap upper diagonal elements with lower diagonal elements of matrix.
• Sparse Matrix Representations
• Ways of filling matrix such that product of all rows and all columns are equal to unity
• Mirror of matrix across diagonal
• Find if there is a rectangle in binary matrix with corners as 1
• Find all rectangles filled with 0
• Shortest distance between two cells in a matrix or grid
• Counting sets of 1s and 0s in a binary matrix
• Search in a row wise and column wise sorted matrix
• Create a matrix with alternating rectangles of O and X
• Zigzag (or diagonal) traversal of Matrix
• Inplace (Fixed space) M x N size matrix transpose | Updated
• Minimum cost to sort a matrix of numbers from 0 to n^2 – 1
• Unique cells in a binary matrix
• Count entries equal to x in a special matrix
• Check if a given matrix is sparse or not
• Row-wise common elements in two diagonals of a square matrix
• Check if sums of i-th row and i-th column are same in matrix
• Find row number of a binary matrix having maximum number of 1s
• Program to check if a matrix is symmetric
• Find if a 2-D array is completely traversed or not by following the cell values
• Program to Print Matrix in Z form
• Print all palindromic paths from top left to bottom right in a matrix
• Possible moves of knight
• Efficiently compute sums of diagonals of a matrix
• Boundary elements of a Matrix
• Print a matrix in a spiral form starting from a point
• Print matrix in snake pattern
• Program to Interchange Diagonals of Matrix
• Find difference between sums of two diagonals
• Construct Ancestor Matrix from a Given Binary Tree
• Construct tree from ancestor matrix
• Circular Matrix (Construct a matrix with numbers 1 to m*n in spiral way)
• Program for Sudoku Generator
• Program for Conway’s Game Of Life
• Maximum sum of hour glass in matrix
• Maximum and Minimum in a square matrix.
• Print matrix in antispiral form
• Program to find Normal and Trace of a matrix
• Sort a Matrix in all way increasing order
• Minimum operations required to set all elements of binary matrix
• Print a given matrix in reverse spiral form
• C Program To Check whether Matrix is Skew Symmetric or not
• Sum of matrix element where each elements is integer division of row and column
• Sparse Matrix and its representations
• Find number of transformation to make two Matrix Equal
• Form coils in a matrix
• Sum of matrix in which each element is absolute difference of its row and column numbers
• Check horizontal and vertical symmetry in binary matrix
• Maximum determinant of a matrix with every values either 0 or n
• Sum of both diagonals of a spiral odd-order square matrix
• Find pair of rows in a binary matrix that has maximum bit difference
• Find all permuted rows of a given row in a matrix
• Find perimeter of shapes formed with 1s in binary matrix
• Print cells with same rectangular sums in a matrix
• Print matrix in diagonal pattern
• Maximum difference of sum of elements in two rows in a matrix
• Find pairs with given sum such that elements of pair are in different rows
• Total coverage of all zeros in a binary matrix
• Replace every matrix element with maximum of GCD of row or column
• Count all sorted rows in a matrix
• Queries in a Matrix
• Maximum XOR value in matrix
• Maximum mirrors which can transfer light from bottom to right
• Direction at last square block
• Print K’th element in spiral form of matrix
• Find if given matrix is Toeplitz or not
• Count zeros in a row wise and column wise sorted matrix
• Count Negative Numbers in a Column-Wise and Row-Wise Sorted Matrix
• Find size of the largest ‘+’ formed by all ones in a binary matrix
• Return previous element in an expanding matrix
• Print n x n spiral matrix using O(1) extra space
• Shortest path in a Binary Maze
• Find orientation of a pattern in a matrix
• Find a specific pair in Matrix
• Print maximum sum square sub-matrix of given size
• Common elements in all rows of a given matrix
• In-place convert matrix in specific order
• A Boolean Matrix Question
• Given a Boolean Matrix, find k such that all elements in k’th row are 0 and k’th column are 1.
• Print unique rows in a given boolean matrix
• Find the largest rectangle of 1’s with swapping of columns allowed
• Validity of a given Tic-Tac-Toe board configuration
• Submatrix Sum Queries
• Program for Rank of Matrix
• Maximum size rectangle binary sub-matrix with all 1s
• Maximum size square sub-matrix with all 1s
• Find sum of all elements in a matrix except the elements in row and/or column of given cell?
• Count number of islands where every island is row-wise and column-wise separated
• Find a common element in all rows of a given row-wise sorted matrix
• Given a matrix of ‘O’ and ‘X’, replace ‘O’ with ‘X’ if surrounded by ‘X’
• Given a matrix of ‘O’ and ‘X’, find the largest subsquare surrounded by ‘X’
• Flood fill Algorithm – how to implement fill() in paint?
• Print all elements in sorted order from row and column wise sorted matrix
• Given an n x n square matrix, find sum of all sub-squares of size k x k
• Program to find transpose of a matrix
• C program for addition of two matrices
• C program for subtraction of matrices
• Collect maximum points in a grid using two traversals
• Collect maximum coins before hitting a dead end
• Number of paths with exactly k coins
• Find length of the longest consecutive path from a given starting character
• Find the longest path in a matrix with given constraints
• Minimum Initial Points to Reach Destination
• Divide and Conquer | Set 5 (Strassen’s Matrix Multiplication)
• Dynamic Programming | Set 27 (Maximum sum rectangle in a 2D matrix)

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