🕷️ Crawler Inspector

  Debugging... Submit 00:00:00 [Register](https://leetcode.com/accounts/signup/?next=%2Fproblems%2Fvalid-sudoku%2Fdescription%2F)or[Log in](https://leetcode.com/accounts/login/?next=%2Fproblems%2Fvalid-sudoku%2Fdescription%2F) [Premium](https://leetcode.com/subscribe/?ref=lp_pl&source=qd) Description Description Editorial Editorial Solutions Solutions Submissions Submissions Code Code Testcase Testcase Test Result Test Result [36\. Valid Sudoku](https://leetcode.com/problems/valid-sudoku/) Medium Topics Companies Determine if a `9 x 9` Sudoku board is valid. Only the filled cells need to be validated **according to the following rules**: 1. Each row must contain the digits `1-9` without repetition. 2. Each column must contain the digits `1-9` without repetition. 3. 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. **Example 1:**  ``` Input: 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"]] Output: true ``` **Example 2:** ``` Input: 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"]] Output: false Explanation: Same as Example 1, except with the 5 in the top left corner being modified to 8. Since there are two 8's in the top left 3x3 sub-box, it is invalid. ``` **Constraints:** - `board.length == 9` - `board[i].length == 9` - `board[i][j]` is a digit `1-9` or `'.'`. Accepted 2,458,364/3.8M Acceptance Rate 64\.3% *** Topics [Array](https://leetcode.com/tag/array/)[Hash Table](https://leetcode.com/tag/hash-table/)[Matrix](https://leetcode.com/tag/matrix/) ***  Companies *** Similar Questions [Sudoku Solver](https://leetcode.com/problems/sudoku-solver/) Hard [Check if Every Row and Column Contains All Numbers](https://leetcode.com/problems/check-if-every-row-and-column-contains-all-numbers/) Easy *** Discussion (321) Choose a type Comment 💡 Discussion Rules 1\. Please don't post **any solutions** in this discussion. 2\. The problem discussion is for asking questions about the problem or for sharing tips - anything except for solutions. 3\. If you'd like to share your solution for feedback and ideas, please head to the solutions tab and post it there. Sort by:Best No comments yet. 1 2 3 4 33 Copyright © 2026 LeetCode. All rights reserved. 12\.5K 321 142 Online 1 Ln 1, Col 1 Case 1 Case 2 board = \[\["5","3",".",".","7",".",".",".","."\],\["6",".",".","1","9","5",".",".","."\],\[".","9","8",".",".",".",".","6","."\],\["8",".",".",".","6",".",".",".","3"\],\["4",".",".","8",".","3",".",".","1"\],\["7",".",".",".","2",".",".",".","6"\],\[".","6",".",".",".",".","2","8","."\],\[".",".",".","4","1","9",".",".","5"\],\[".",".",".",".","8",".",".","7","9"\]\] 9 1 2 › \[\["5","3",".",".","7",".",".",".","."\],\["6",".",".","1","9","5",".",".","."\],\[".","9","8",".",".",".",".","6","."\],\["8",".",".",".","6",".",".",".","3"\],\["4",".",".","8",".","3",".",".","1"\],\["7",".",".",".","2",".",".",".","6"\],\[".","6",".",".",".",".","2","8","."\],\[".",".",".","4","1","9",".",".","5"\],\[".",".",".",".","8",".",".","7","9"\]\] \[\["8","3",".",".","7",".",".",".","."\],\["6",".",".","1","9","5",".",".","."\],\[".","9","8",".",".",".",".","6","."\],\["8",".",".",".","6",".",".",".","3"\],\["4",".",".","8",".","3",".",".","1"\],\["7",".",".",".","2",".",".",".","6"\],\[".","6",".",".",".",".","2","8","."\],\[".",".",".","4","1","9",".",".","5"\],\[".",".",".",".","8",".",".","7","9"\]\] Source FindHeaderBarSize FindTabBarSize FindBorderBarSize

Determine if a `9 x 9` Sudoku board is valid. Only the filled cells need to be validated **according to the following rules**: 1. Each row must contain the digits `1-9` without repetition. 2. Each column must contain the digits `1-9` without repetition. 3. 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. **Example 1:**  ``` Input: 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"]] Output: true ``` **Example 2:** ``` Input: 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"]] Output: false Explanation: Same as Example 1, except with the 5 in the top left corner being modified to 8. Since there are two 8's in the top left 3x3 sub-box, it is invalid. ``` **Constraints:** - `board.length == 9` - `board[i].length == 9` - `board[i][j]` is a digit `1-9` or `'.'`.