Given a number n, the task is to check if it is divisible by 7 or not. Note: You are not allowed to use the modulo operator, floating point arithmetic is also not allowed. Examples: Input: n = 371 Output: True Explanation: The number 371: 37 - (2×1) = 37 - 2 = 35; 3 - (2 × 5) = 3 - 10 = -7; thus,…

Try it on GfG Practice Given a string of brackets, the task is to find an index k which decides the number of opening brackets is equal to the number of closing brackets. The string must be consists of only opening and closing brackets i.e. '(' and ')'. An equal point is an index such that the…

Try it on GfG Practice Given a lowercase English string s of length n, encrypt it as follows: Replace each contiguous group of the same character with the character followed by the lowercase hexadecimal representation of its length.Reverse the entire modified string. Return the encrypted string.…

Try it on GfG Practice Given a string in roman form, the task is to convert this given roman string into an integer. Roman numerals are based on the symbols I, V, X, L, C, D, and M, which represent 1, 5, 10, 50, 100, 500, and 1,000 respectively. Different arrangements of these symbols represent…

Try it on GfG Practice Given an integer, convert it into its equivalent Roman numeral representation. Note: Following is the list of Roman symbols (including subtractive cases): SymbolValueI1IV4V5IX9X10XL40L50XC90C100CD400D500CM900M1000Examples: Input: 9 Output: IX Explanation: 9 is written as "IX"…

Given an array of strings arr[], the task is to return the longest common prefix among each and every strings present in the array. If there’s no prefix common in all the strings, return “”. Examples: Input: arr[] = [“geeksforgeeks”, “geeks”, “geek”, “geezer”] Output: “gee” Explanation: “gee” is the…

Try it on GfG Practice Given a string str, your task is to reverse the order of the words in the given string. Note that str may contain leading or trailing dots(.) or multiple trailing dots(.) between two words. The returned string should only have a single dot(.) separating the words. Examples:…

Given a matrix mat[n][m] and an element target. return true if the target is present in the matrix, else return false. Examples: Input : mat[][] = { {10, 51, 9}, {14, 20, 21}, {30, 24, 43} } target = 14 Output: Found Input : mat[][] = {{31, 5, 9, 11}, {14, 7, 21, 26}, {30, 4, 43, 50} } target = 42…

Two common ways of traversing a matrix are row-major-order and column-major-order Row Major Order: When matrix is accessed row by row. Column Major Order: When matrix is accessed column by column. Examples: Input : mat[][] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}} Output : Row-wise: 1 2 3 4 5 6 7 8 9…

Matrix or Grid is a two-dimensional array mostly used in mathematical and scientific calculations. It is also considered as an array of arrays, where array at each index has the same size. Representation of Matrix Data Structure: As you can see from the below image, the elements are organized in…

Given a m*n grid with each cell consisting of positive, negative, or no points i.e., zero points. From a cell (i, j) we can move to (i+1, j) or (i, j+1) and we can move to a cell only if we have positive points ( > 0 ) when we move to that cell. Whenever we pass through a cell, points in that cell…

Given an integer k, the task is to generate a 9 x 9 Sudoku grid having k empty cells while following the below set of rules: In all 9 submatrices 3x3, the elements should be 1-9, without repetition.In all rows, there should be elements between 1-9, without repetition.In all columns, there should be…

Try it on GfG Practice Given a sorted matrix mat[][] of size nxm and an element x, the task is to find if x is present in the matrix or not. Matrix is sorted in a way such that all elements in a row are sorted in increasing order and for row i, where 1 <= i <= n-1, the first element of row i is…

Given two m x n matrices m1 and m2, the task is to subtract m2 from m1 and return res. Input: m1 = {{1, 2}, {3, 4}}, m2 = {{4, 3}, {2, 1}} Output: {{-3, -1}, {1, 3}} Input: m1 = {{3, 3, 3}, {3, 3, 3}}, m1 = {{2, 2, 2}, {1, 1, 1}}, Output: {{1, 1, 1}, {2, 2, 2}}, We traverse both matrices element by…

Try it on GfG Practice Given two N x M matrices. Find a N x M matrix as the sum of given matrices each value at the sum of values of corresponding elements of the given two matrices. Approach: Below is the idea to solve the problem. Iterate over every cell of matrix (i, j), add the corresponding…

Given an n × n binary matrix mat consisting of 0s and 1s. Your task is to find the size of the largest ‘+’ shape that can be formed using only 1s. A ‘+’ shape consists of a center cell with four arms extending in all four directions (up, down, left, and right) while remaining within the matrix…

Try it on GfG Practice Given a matrix of size n * m. You have to find the kth element which will obtain while traversing the matrix spirally starting from the top-left corner of the matrix. Examples: Input: mat[][] = [ [1, 2, 3], [4, 5, 6], [7, 8, 9] ], k = 4 Output: 6 Explanation: Spiral traversal…

Given a Binary Tree where all values are from 0 to n-1. Construct an ancestor matrix mat[n][n] where the ancestor matrix is defined as below. mat[i][j] = 1 if i is ancestor of jmat[i][j] = 0, otherwise Examples: Input: Output: {{0 1 1} {0 0 0} {0 0 0}} Input: Output: {{0 0 0 0 0 0} {1 0 0 0 1 0} {0…

Try it on GfG Practice Given a 2d binary matrix mat[][], the task is to find the maximum size rectangle binary-sub-matrix with all 1's. Examples: Input: mat = [ [0, 1, 1, 0], [1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 0, 0] ] Output : 8 Explanation : The largest rectangle with only 1's is from (1, 0) to (2,…

Given a matrix where every row is sorted in increasing order. Write a function that finds and returns a common element in all rows. If there is no common element, then returns -1. Example: Input: mat[4][5] = { {1, 2, 3, 4, 5}, {2, 4, 5, 8, 10}, {3, 5, 7, 9, 11}, {1, 3, 5, 7, 9}, }; Output: 5 A…

Given a positive integer n, your task is to generate a magic square of order n * n. A magic square of order n is an n * n grid filled with the numbers 1 through n² so that every row, every column, and both main diagonals each add up to the same total, called the magic constant (or magic sum) M.…

Given a Binary Matrix mat[][] of size n x n, consisting of 1s and 0s. The task is to find the minimum flips required to make the matrix symmetric along the main diagonal. Examples : Input: mat[][] = [[0, 0, 1], [1, 1, 1], [1, 0, 0]]; Output: 2 Value of mat[1][0] is not equal to mat[0][1]. Value of…

Given an M x N matrix, transpose the matrix without auxiliary memory.It is easy to transpose matrix using an auxiliary array. If the matrix is symmetric in size, we can transpose the matrix inplace by mirroring the 2D array across it's diagonal (try yourself). How to transpose an arbitrary size…

Given two matrices a and b of size n*m. The task is to find the required number of transformation steps so that both matrices become equal. Print -1 if this is not possible. The transformation step is as follows: Select any one matrix out of two matrices. Choose either row/column of the selected…

Given a matrix mat[][] of order m*n, and an index ind. The task is to find all the rows in the matrix mat[][] which are permutations of rows at index ind. Note: All the elements of a row are distinct. Examples: Input: mat[][] = [[3, 1, 4, 2], [1, 6, 9, 3], [1, 2, 3, 4], [4, 3, 2, 1]] ind = 3 Output:…

Try it on GfG Practice Given two sorted matrices mat1 and mat2 of size n x n of distinct elements. Given a value x, the task is to count all pairs from both matrices whose sum is equal to x. Note: The pair has an element from each matrix. Matrices are strictly sorted which means that matrices are…

Given two integers m and n, that describes the order m*n of a matrix mat[][], initially filled with integers from 1 to m*n sequentially in a row-major order. Also, there is a 2d array query[][] consisting of q queries, which contains three integers each, where the first integer t describes the type…

Try it on GfG Practice Given a n x n binary matrix (elements in matrix can be either 1 or 0) where each row and column of the matrix is sorted in ascending order, count number of 0s present in it. Examples: Input: [0, 0, 0, 0, 1] [0, 0, 0, 1, 1] [0, 1, 1, 1, 1] [1, 1, 1, 1, 1] [1, 1, 1, 1, 1]…

Given a matrix of n*n size, the task is to find whether all rows are circular rotations of each other or not. Examples: Input: mat[][] = 1, 2, 3 3, 1, 2 2, 3, 1 Output: Yes All rows are rotated permutation of each other. Input: mat[3][3] = 1, 2, 3 3, 2, 1 1, 3, 2 Output: No Explanation : As 3, 2, 1…

Given a Binary Matrix mat[][] of order m*n. A cell with a value of zero is a Dead Cell, while a cell with a value of one is a Live Cell. The state of cells in a matrix mat[][] is known as Generation. The task is to find the next generation of cells based on the following rules: Any live cell with…

Given a chess board of dimension m * n. Find number of possible moves where knight can be moved on a chessboard from given position. If mat[i][j] = 1 then the block is filled by something else, otherwise empty. Assume that board consist of all pieces of same color, i.e., there are no blocks being…

Given a square matrix mat[][] of order n, your task is to check if it is a Toeplitz Matrix. Note: A Toeplitz matrix - also called a diagonal-constant matrix - is a matrix where elements of every individual descending diagonal are same from left to right. Equivalently, for any entry mat[i][j], it is…

Given a 2-D array of order N x N, print a matrix that is the mirror of the given tree across the diagonal. We need to print the result in a way: swap the values of the triangle above the diagonal with the values of the triangle below it like a mirror image swap. Print the 2-D array obtained in a…

Given a square matrix mat[][] of order n*n, the task is to check if it is an Identity Matrix. Identity Matrix: A square matrix is said to be an identity matrix if the elements of main diagonal are one and all other elements are zero. The identity Matrix is also known as the Unit Matrix. Examples:…

Given a square matrix mat[][] of order n*n, the task is to check if it is a Diagonal Matrix and Scalar matrix. Diagonal Matrix: A square matrix is said to be a diagonal matrix if the elements of the matrix except the main diagonal are zero. A square null matrix is also a diagonal matrix whose main…

Given a square matrix mat[][] of order n*n, the task is to check if it is an Idempotent Matrix or not. Idempotent matrix: A matrix is said to be an idempotent matrix if the matrix multiplied by itself returns the same matrix, i.e. the matrix mat[][] is said to be an idempotent matrix if and only if…

Given an integer matrix of odd dimensions (3 * 3, 5 * 5). then the task is to find the sum of the middle row & column elements. Examples: Input : 2 5 7 3 7 2 5 6 9 Output : Sum of middle row = 12 Sum of middle column = 18 Input : 1 3 5 6 7 3 5 3 2 1 1 2 3 4 5 7 9 2 1 6 9 1 5 3 2 Output : Sum of…

Given an integer matrix mat[][] of odd dimensions, the task is to find the square of the elements of the Primary and Secondary diagonals. The Primary and Secondary diagonal matrix explanation is given below: Primary Diagonal Elements of a Matrix: The Primary Diagonal Elements are the ones that occur…

Given a square matrix mat[][] of order n*n, the task is to swap the elements of major and minor diagonals. The major and minor diagonal matrix explanation is given below: Major Diagonal Elements of a Matrix: The Major Diagonal Elements are the ones that occur from the Top Left of the Matrix Down To…

Given a square matrix mat[][] and a number k. The task is to shift the first k elements of each row to the right of the matrix. Examples : Input : mat[N][N] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}} k = 2 Output :mat[N][N] = {{3, 1, 2} {6, 4, 5} {9, 7, 8}} Input : mat[N][N] = {{1, 2, 3, 4} {5, 6, 7, 8}…