LLM generated sudoku solver

solve.py

def find_empty(grid):
    for i in range(9):
        for j in range(9):
            if grid[i][j] == 0:
                return i, j  # row, column
    return None  # no empty spaces in the grid

def is_valid(grid, num, pos):
    # Check if num is already in the row or column
    for i in range(9):
        if grid[pos[0]][i] == num or grid[i][pos[1]] == num:
            return False

    # Check if num is already in the box
    box_x = pos[1] // 3
    box_y = pos[0] // 3
    for i in range(box_y * 3, box_y * 3 + 3):
        for j in range(box_x * 3, box_x * 3 + 3):
            if grid[i][j] == num:
                return False

    return True

def solve(grid):
    find = find_empty(grid)
    if not find:
        return True  # all cells are filled
    else:
        row, col = find

    for i in range(1, 10):  # try digits from 1 to 9
        if is_valid(grid, i, (row, col)):
            grid[row][col] = i
            if solve(grid):  # recursively try to fill the rest of the grid
                return True

            grid[row][col] = 0  # undo if no solution can be found

    return False  # no solution

grid =     [
        [4,9,6,0,7,0,0,0,0],
        [0,0,8,9,0,3,0,0,0],
        [7,5,0,8,0,2,0,1,9],
        [0,0,0,0,0,0,0,2,5],
        [0,0,1,7,2,0,4,9,0],
        [8,0,7,0,9,0,3,6,0],
        [0,8,0,0,0,7,9,0,0],
        [0,6,0,0,5,4,0,3,0],
        [0,0,0,2,8,9,1,5,6]
    ]
print(solve(
    grid
))
for row in grid:
    print(row)

grid =    [
        [0,0,6,0,0,0,0,0,1],
        [0,3,0,0,0,0,8,0,0],
        [0,0,0,5,0,8,4,0,0],
        [0,6,0,0,1,0,0,2,0],
        [0,0,3,0,0,7,0,0,0],
        [0,9,1,0,0,0,3,0,0],
        [0,0,0,0,0,5,1,7,0],
        [1,5,0,0,2,6,0,0,0],
        [0,0,0,0,9,0,6,5,0],
    ]
print(solve(
    grid
))
for row in grid:
    print(row)