matrix.validate_sudoku_board

LeetCode 36. Valid Sudoku https://leetcode.com/problems/valid-sudoku/ https://en.wikipedia.org/wiki/Sudoku

Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:

• Each row must contain the digits 1-9 without repetition.

• Each column must contain the digits 1-9 without repetition.

• Each of the nine 3 x 3 sub-boxes of the grid must contain the digits 1-9 without repetition.

Note:

A Sudoku board (partially filled) could be valid but is not necessarily solvable.

Only the filled cells need to be validated according to the mentioned rules.

Attributes

EMPTY_CELL
NUM_SQUARES

Functions

is_valid_sudoku_board(→ bool)

This function validates (but does not solve) a sudoku board.

Module Contents

matrix.validate_sudoku_board.is_valid_sudoku_board(sudoku_board: list[list[str]]) → bool

This function validates (but does not solve) a sudoku board. The board may be valid but unsolvable.

>>> is_valid_sudoku_board([
...  ["5","3",".",".","7",".",".",".","."]
... ,["6",".",".","1","9","5",".",".","."]
... ,[".","9","8",".",".",".",".","6","."]
... ,["8",".",".",".","6",".",".",".","3"]
... ,["4",".",".","8",".","3",".",".","1"]
... ,["7",".",".",".","2",".",".",".","6"]
... ,[".","6",".",".",".",".","2","8","."]
... ,[".",".",".","4","1","9",".",".","5"]
... ,[".",".",".",".","8",".",".","7","9"]
... ])
True
>>> is_valid_sudoku_board([
...  ["8","3",".",".","7",".",".",".","."]
... ,["6",".",".","1","9","5",".",".","."]
... ,[".","9","8",".",".",".",".","6","."]
... ,["8",".",".",".","6",".",".",".","3"]
... ,["4",".",".","8",".","3",".",".","1"]
... ,["7",".",".",".","2",".",".",".","6"]
... ,[".","6",".",".",".",".","2","8","."]
... ,[".",".",".","4","1","9",".",".","5"]
... ,[".",".",".",".","8",".",".","7","9"]
... ])
False
>>> is_valid_sudoku_board([
...  ["1","2","3","4","5","6","7","8","9"]
... ,["4","5","6","7","8","9","1","2","3"]
... ,["7","8","9","1","2","3","4","5","6"]
... ,[".",".",".",".",".",".",".",".","."]
... ,[".",".",".",".",".",".",".",".","."]
... ,[".",".",".",".",".",".",".",".","."]
... ,[".",".",".",".",".",".",".",".","."]
... ,[".",".",".",".",".",".",".",".","."]
... ,[".",".",".",".",".",".",".",".","."]
... ])
True
>>> is_valid_sudoku_board([
...  ["1","2","3",".",".",".",".",".","."]
... ,["4","5","6",".",".",".",".",".","."]
... ,["7","8","9",".",".",".",".",".","."]
... ,[".",".",".","4","5","6",".",".","."]
... ,[".",".",".","7","8","9",".",".","."]
... ,[".",".",".","1","2","3",".",".","."]
... ,[".",".",".",".",".",".","7","8","9"]
... ,[".",".",".",".",".",".","1","2","3"]
... ,[".",".",".",".",".",".","4","5","6"]
... ])
True
>>> is_valid_sudoku_board([
...  ["1","2","3",".",".",".","5","6","4"]
... ,["4","5","6",".",".",".","8","9","7"]
... ,["7","8","9",".",".",".","2","3","1"]
... ,[".",".",".","4","5","6",".",".","."]
... ,[".",".",".","7","8","9",".",".","."]
... ,[".",".",".","1","2","3",".",".","."]
... ,["3","1","2",".",".",".","7","8","9"]
... ,["6","4","5",".",".",".","1","2","3"]
... ,["9","7","8",".",".",".","4","5","6"]
... ])
True
>>> is_valid_sudoku_board([
...  ["1","2","3","4","5","6","7","8","9"]
... ,["2",".",".",".",".",".",".",".","8"]
... ,["3",".",".",".",".",".",".",".","7"]
... ,["4",".",".",".",".",".",".",".","6"]
... ,["5",".",".",".",".",".",".",".","5"]
... ,["6",".",".",".",".",".",".",".","4"]
... ,["7",".",".",".",".",".",".",".","3"]
... ,["8",".",".",".",".",".",".",".","2"]
... ,["9","8","7","6","5","4","3","2","1"]
... ])
False
>>> is_valid_sudoku_board([
...  ["1","2","3","8","9","7","5","6","4"]
... ,["4","5","6","2","3","1","8","9","7"]
... ,["7","8","9","5","6","4","2","3","1"]
... ,["2","3","1","4","5","6","9","7","8"]
... ,["5","6","4","7","8","9","3","1","2"]
... ,["8","9","7","1","2","3","6","4","5"]
... ,["3","1","2","6","4","5","7","8","9"]
... ,["6","4","5","9","7","8","1","2","3"]
... ,["9","7","8","3","1","2","4","5","6"]
... ])
True
>>> is_valid_sudoku_board([["1", "2", "3", "4", "5", "6", "7", "8", "9"]])
Traceback (most recent call last):
    ...
ValueError: Sudoku boards must be 9x9 squares.
>>> is_valid_sudoku_board(
...        [["1"], ["2"], ["3"], ["4"], ["5"], ["6"], ["7"], ["8"], ["9"]]
...  )
Traceback (most recent call last):
    ...
ValueError: Sudoku boards must be 9x9 squares.

matrix.validate_sudoku_board.EMPTY_CELL = '.'

matrix.validate_sudoku_board.NUM_SQUARES = 9