Given a 9 × 9 Sudoku board, determine whether it is valid. A board is considered valid if all of the following conditions hold (considering only the filled cells):
Each row contains the digits 1–9 at most once.
Each column contains the digits 1–9 at most once.
Each of the nine 3 × 3 sub-boxes contains the digits 1–9 at most once.
You do not need to check whether the Sudoku is solvable; only whether the current filled entries obey these rules.
Note: A partially filled Sudoku board can be valid even if it is not necessarily solvable. You only need to verify that the filled cells adhere to the given rules.
Constraints:
board.length
board[i].length
Given a 9 × 9 Sudoku board, determine whether it is valid. A board is considered valid if all of the following conditions hold (considering only the filled cells):
Each row contains the digits 1–9 at most once.
Each column contains the digits 1–9 at most once.
Each of the nine 3 × 3 sub-boxes contains the digits 1–9 at most once.
You do not need to check whether the Sudoku is solvable; only whether the current filled entries obey these rules.
Note: A partially filled Sudoku board can be valid even if it is not necessarily solvable. You only need to verify that the filled cells adhere to the given rules.
Constraints:
board.length
board[i].length