Category

Technical

Marketing sub-category

Model

ChatGPT 4

Technical sub-categories

Development

## Prompt

Your task is to create Python functions based on the provided natural language requests. The requests will describe the desired functionality of the function, including the input parameters and expected return value. Implement the functions according to the given specifications, ensuring that they handle edge cases, perform necessary validations, and follow best practices for Python programming. Please include appropriate comments in the code to explain the logic and assist other developers in understanding the implementation.[function description]

## Sample query

Your task is to create Python functions based on the provided natural language requests. The requests will describe the desired functionality of the function, including the input parameters and expected return value. Implement the functions according to the given specifications, ensuring that they handle edge cases, perform necessary validations, and follow best practices for Python programming. Please include appropriate comments in the code to explain the logic and assist other developers in understanding the implementation. I want a function that can solve a Sudoku puzzle. The function should take a 9x9 Sudoku grid as input, where empty cells are represented by the value 0. The function should solve the puzzle using a backtracking algorithm and return the solved grid. If the puzzle is unsolvable, it should return None. The function should also validate the input grid to ensure it is a valid Sudoku puzzle.

## Sample response

Here's a Python function that solves a Sudoku puzzle using a backtracking algorithm and validates the input grid:

```
def is_valid_sudoku(grid):
"""
Check if the given Sudoku grid is valid.
"""
# Check rows
for row in grid:
if not is_valid_row(row):
return False
# Check columns
for col in range(9):
column = [grid[row][col] for row in range(9)]
if not is_valid_row(column):
return False
# Check 3x3 subgrids
for i in range(0, 9, 3):
for j in range(0, 9, 3):
subgrid = [grid[x][y] for x in range(i, i+3) for y in range(j, j+3)]
if not is_valid_row(subgrid):
return False
return True
def is_valid_row(row):
"""
Check if a row is valid (no duplicates except for 0).
"""
seen = set()
for num in row:
if num != 0:
if num in seen:
return False
seen.add(num)
return True
def solve_sudoku(grid):
"""
Solve the Sudoku puzzle using backtracking.
"""
if not is_valid_sudoku(grid):
return None
empty_cell = find_empty_cell(grid)
if not empty_cell:
return grid
row, col = empty_cell
for num in range(1, 10):
if is_safe(grid, row, col, num):
grid[row][col] = num
if solve_sudoku(grid):
return grid
grid[row][col] = 0 # Backtrack if the current configuration is invalid
return None
def find_empty_cell(grid):
"""
Find the first empty cell (cell with value 0) in the Sudoku grid.
"""
for i in range(9):
for j in range(9):
if grid[i][j] == 0:
return (i, j)
return None
def is_safe(grid, row, col, num):
"""
Check if it's safe to place 'num' in the given position.
"""
# Check row
if num in grid[row]:
return False
# Check column
if num in [grid[i][col] for i in range(9)]:
return False
# Check 3x3 subgrid
start_row, start_col = 3 * (row // 3), 3 * (col // 3)
for i in range(start_row, start_row + 3):
for j in range(start_col, start_col + 3):
if grid[i][j] == num:
return False
return True
```

This code defines several helper functions:

`is_valid_sudoku(grid)`

: Checks if the given Sudoku grid is valid according to Sudoku rules.`is_valid_row(row)`

: Checks if a given row in the Sudoku grid is valid (no duplicates except for 0).`solve_sudoku(grid)`

: Solves the Sudoku puzzle using backtracking.`find_empty_cell(grid)`

: Finds the first empty cell (cell with value 0) in the Sudoku grid.`is_safe(grid, row, col, num)`

: Checks if it's safe to place a number in a given position in the Sudoku grid.

The `solve_sudoku`

function starts solving the Sudoku puzzle by recursively trying to fill each empty cell with a valid number. If a solution is found, it returns the solved grid. If the puzzle is unsolvable, it returns None.