Valid Sudoku Board

Problem

Return True if a partially filled 9 by 9 Sudoku board has no duplicate digits in any row, column or 3 by 3 box, where empty cells are the character dot.

Validate the three constraint types independently using sets. The board is considered valid regardless of whether it can be completed.

Hint

A 3 by 3 box index is (row // 3) * 3 + column // 3; validate rows, columns and boxes separately.

Test cases

case 1

in: [[["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4","…

expected: true

case 2

in: [[["8","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4","…

expected: false

case 3

in: [[["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],["5","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4","…

expected: false

case 4

in: [[["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4","…

expected: false

case 5

in: [[[".",".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".",".","."],[".","…

expected: true

Starter codePython

def is_valid_sudoku(board):
    # Your code here
    pass

5 test cases · run your code against them in the editor