""" In this problem, we want to rotate the matrix elements by 90, 180, 270 (counterclockwise) Discussion in stackoverflow: https://stackoverflow.com/questions/42519/how-do-you-rotate-a-two-dimensional-array """ from __future__ import annotations def make_matrix(row_size: int = 4) -> list[list]: """ >>> make_matrix() [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]] >>> make_matrix(1) [[1]] >>> make_matrix(-2) [[1, 2], [3, 4]] >>> make_matrix(3) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] >>> make_matrix() == make_matrix(4) True """ row_size = abs(row_size) or 4 return [[1 + x + y * row_size for x in range(row_size)] for y in range(row_size)] def rotate_90(matrix: list[list]) -> list[list]: """ >>> rotate_90(make_matrix()) [[4, 8, 12, 16], [3, 7, 11, 15], [2, 6, 10, 14], [1, 5, 9, 13]] >>> rotate_90(make_matrix()) == transpose(reverse_column(make_matrix())) True """ return reverse_row(transpose(matrix)) # OR.. transpose(reverse_column(matrix)) def rotate_180(matrix: list[list]) -> list[list]: """ >>> rotate_180(make_matrix()) [[16, 15, 14, 13], [12, 11, 10, 9], [8, 7, 6, 5], [4, 3, 2, 1]] >>> rotate_180(make_matrix()) == reverse_column(reverse_row(make_matrix())) True """ return reverse_row(reverse_column(matrix)) # OR.. reverse_column(reverse_row(matrix)) def rotate_270(matrix: list[list]) -> list[list]: """ >>> rotate_270(make_matrix()) [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]] >>> rotate_270(make_matrix()) == transpose(reverse_row(make_matrix())) True """ return reverse_column(transpose(matrix)) # OR.. transpose(reverse_row(matrix)) def transpose(matrix: list[list]) -> list[list]: matrix[:] = [list(x) for x in zip(*matrix)] return matrix def reverse_row(matrix: list[list]) -> list[list]: matrix[:] = matrix[::-1] return matrix def reverse_column(matrix: list[list]) -> list[list]: matrix[:] = [x[::-1] for x in matrix] return matrix def print_matrix(matrix: list[list]) -> None: for i in matrix: print(*i) if __name__ == "__main__": matrix = make_matrix() print("\norigin:\n") print_matrix(matrix) print("\nrotate 90 counterclockwise:\n") print_matrix(rotate_90(matrix)) matrix = make_matrix() print("\norigin:\n") print_matrix(matrix) print("\nrotate 180:\n") print_matrix(rotate_180(matrix)) matrix = make_matrix() print("\norigin:\n") print_matrix(matrix) print("\nrotate 270 counterclockwise:\n") print_matrix(rotate_270(matrix))