# Matrix Data Structure

**Data Structure and Algorithms Course**

**Practice Problems on Matrix**

## What is Matrix in Data Structure?

A matrix represents a collection of numbers arranged in an order of rows and columns. It is necessary to enclose the elements of a matrix in parentheses or brackets.

**For example:**

A matrix with 9 elements is shown below.

This Matrix [M] has 3 rows and 3 columns. Each element of matrix [M] can be referred to by its row and column number. For example, a_{23}= 6.

### Matrix Introduction

### Recent Articles on Matrix

- 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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