Check whether a 9x9 Sudoku board is valid.
Example 1
Input: board = ["83..7....","6..195...",".98....6.","8...6...3","4..8.3..1","7...2...6",".6....28.","...419..5","....8..79"]
Output: False
Explanation: The digit 8 is repeated in the first row and the top-left box.
Output: False
Explanation: The digit 8 is repeated in the first row and the top-left box.
Example 2
Input: board = ["53..7....","6..195...",".98....6.","8...6...3","4..8.3..1","7...2...6",".6....28.","...419..5","....8..79"]
Output: True
Explanation: There are no repeated digits in rows, columns, or 3x3 boxes.
Output: True
Explanation: There are no repeated digits in rows, columns, or 3x3 boxes.
Example 3
Input: board = ["53..7....","6..195...",".98....6.","8...6...3","4..8.3..1","7...2...6",".6....28.","...419..5","....8..76"]
Output: False
Explanation: The digit 6 is repeated in the last column, which violates Sudoku rules.
Output: False
Explanation: The digit 6 is repeated in the last column, which violates Sudoku rules.