In-Place

Problem Overview We are given a 2D matrix of size n * n. The matrix represents an image. Our goal is to rotate the image by 90 degrees clockwise. The solution must use constant extra space (in-place). LeetCode - Rotate Image Example Input: matrix = [[1,2,3], [4,5,6], [7,8,9]] Output: [[7,4,1], [8,5,2], [9,6,3]] Intuition If we remember basic matrix properties: Transpose of a matrix Reverse of each row If we: First take the transpose (swap (i,j) with (j,i)) Then reverse every row We effectively rotate the matrix 90° clockwise. ...

Problem Overview We are given a matrix of size m * n. If any element in the matrix is 0, set its entire row and column to 0. Constraint: The solution must use O(1) extra space. LeetCode - Set Matrix Zeroes Example Input: matrix = [[1,1,1],[1,0,1],[1,1,1]] Output: [[1,0,1],[0,0,0],[1,0,1]] Brute Force Intuition and Approach Use an unordered_map to store positions of original zeros. In a second traversal: ...