Generate a Random Minesweeper Grid with N Mines

Implement a function to generate an initial Minesweeper board. Given R rows, C columns, and N mines, generate an R x C grid. Requirements: Randomly place N mines '*' on distinct cells Fill all other cells with '0'..'8' indicating the number of mines in its 8-neighborhood No duplicate mine positions You may use a PRNG (e.g., random.randint). Input R C N Output Print R lines, each with C characters (no spaces), consisting of '*' or '0'..'8' Constraints 1 <= R, C <= 2000 0 <= N <= R*C Aim for near O(R*C + N) time and minimal extra space Notes on tests Random outputs are inherently non-deterministic; tests below validate edge cases and correctness rather than exact mine positions. Example Input 1 1 0 Output 0