Matrix

Problem You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with m rows and n columns using all the elements from original. The elements from indices 0 to n - 1 (inclusive) of original should form the first row of the constructed 2D array, the elements from indices n to 2 * n - 1 (inclusive) should form the second row of the constructed 2D array, and so on. ...

Problem You start at the cell (rStart, cStart) of an rows x cols grid facing east. The northwest corner is at the first row and column in the grid, and the southeast corner is at the last row and column. You will walk in a clockwise spiral shape to visit every position in this grid. Whenever you move outside the grid’s boundary, we continue our walk outside the grid (but may return to the grid boundary later.). Eventually, we reach all rows * cols spaces of the grid. ...

Problem You are given two arrays rowSum and colSum of non-negative integers where rowSum[i] is the sum of the elements in the ith row and colSum[j] is the sum of the elements of the jth column of a 2D matrix. In other words, you do not know the elements of the matrix, but you do know the sums of each row and column. Find any matrix of non-negative integers of size rowSum.length x colSum.length that satisfies the rowSum and colSum requirements. ...

Problem Given an m x n matrix of distinct numbers, return all lucky numbers in the matrix in any order. A lucky number is an element of the matrix such that it is the minimum element in its row and maximum in its column. Examples Example 1: $$ matrix = \begin{bmatrix} 3 & 7 & 8 \\ 9 & 11 & 13 \\ \colorbox{green} {15} & 16 & 17 \end{bmatrix} $$ ...

Problem You are given a 0-indexed 2D matrix grid of size n x n, where (r, c) represents: A cell containing a thief if grid[r][c] = 1 An empty cell if grid[r][c] = 0 You are initially positioned at cell (0, 0). In one move, you can move to any adjacent cell in the grid, including cells containing thieves. The safeness factor of a path on the grid is defined as the minimum manhattan distance from any cell in the path to any thief in the grid. ...

Problem There are a row of n houses, each house can be painted with one of the k colors. The cost of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent houses have the same color. The cost of painting each house with a certain color is represented by a n x k cost matrix. For example, costs[0][0] is the cost of painting house 0 with color 0; costs[1][2] is the cost of painting house 1 with color 2, and so on… Find the minimum cost to paint all houses. ...

Problem You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). Another way to ask the same problem Given an image represented by an NxN matrix, where each pixel in the image is 4 bytes, write a method to rotate the image by 90 degrees. Can you do this in place? Examples Example 1: ...

Problem Given an m x n matrix, return all elements of the matrix in spiral order. Examples Example 1: Input: matrix = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] Output: [1,2,3,6,9,8,7,4,5] Example 2: Input: matrix = [ [1,2,3,4],[5,6,7,8],[9,10,11,12] ] Output: [1,2,3,4,8,12,11,10,9,5,6,7] ...

Problem Solve a well-posed sudoku puzzle. What Sudoku is a popular game that many of you are familiar with. The main idea of the game is to fill a grid with only the numbers from 1 to 9, while ensuring that each row and each column as well as each sub-grid of 9 elements does not contain duplicate numbers. Examples Example 1: ...

Problem Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Each row must contain the digits 1-9 without repetition. Each column must contain the digits 1-9 without repetition. Each of the nine 3 x 3 sub-boxes of the grid must contain the digits 1-9 without repetition. Note: A Sudoku board (partially filled) could be valid but is not necessarily solvable. Only the filled cells need to be validated according to the mentioned rules. The Sudoku board could be partially filled, where empty cells are filled with the character ‘.’. ...