Solve sudoku fast AF

SudokuSolver.py

def find_next_empty(puzzle):
    for r in range(9):
        for c in range(9):
            if puzzle[r][c] == 0:
                return r, c
    return None, None


def is_valid(guess, puzzle, row, col):
    # First check the rows
    row_vals = puzzle[row]
    if guess in row_vals:
        return False

    # Then check the cols, a bit trciky but manageable
    col_vals = [puzzle[c][col] for c in range(9)]
    if guess in col_vals:
        return False

    # Now comes the matrix, my expectations for you were low but holy F!
    mtx_row = (row // 3) * 3
    mtx_col = (col // 3) * 3
    for r in range(mtx_row, mtx_row + 3):
        for c in range(mtx_col, mtx_col + 3):
            if puzzle[r][c] == guess:
                return False

    return True


count = 0


def solve_sudoku(puzzle):
    global count
    count += 1
    row, col = find_next_empty(puzzle)

    # Means, there is nothing left to fill, base case for recursion
    # It also means that problem is complete in language of hoomans
    if row is None:
        return True

    # Otherwise, make a guess, and check if that guess is valid
    for guess in range(1, 10):
        if is_valid(guess, puzzle, row, col):
            puzzle[row][col] = guess

            if solve_sudoku(puzzle):
                return True
            puzzle[row][col] = 0

    # Otherwise, by the power of GOD, I hereby declare that this puzzle is impossible to solve
    return False


def printsudoku(sudoku):
    print()
    for i in range(len(sudoku)):
        line = ""
        if i == 3 or i == 6:
            print("---------------------")
        for j in range(len(sudoku[i])):
            if j == 3 or j == 6:
                line += "| "
            line += str(sudoku[i][j]) + " "
        print(line)


def run():
    matrix = [
        [0, 0, 5, 3, 0, 0, 0, 0, 0],
        [8, 0, 0, 0, 0, 0, 0, 2, 0],
        [0, 7, 0, 0, 1, 0, 5, 0, 0],
        [4, 0, 0, 0, 0, 5, 3, 0, 0],
        [0, 1, 0, 0, 7, 0, 0, 0, 6],
        [0, 0, 3, 2, 0, 0, 0, 8, 0],
        [0, 6, 0, 5, 0, 0, 0, 0, 9],
        [0, 0, 4, 0, 0, 0, 0, 3, 0],
        [0, 0, 0, 0, 0, 9, 7, 0, 0],
    ]

    if solve_sudoku(matrix):
        printsudoku(matrix)
        print("\nSolved Sudoku successfully. It took me %d tries :]" % count)
    else:
        print("\nBy the law of GOD, this Sudoku is unsolvable.")
        print("Trust me, I tried all %d possible combinations." % count)


if __name__ == '__main__':
    run()