🕷️ Crawler Inspector

  Debugging... Submit 00:00:00 [Register](https://leetcode.com/accounts/signup/?next=%2Fproblems%2Fsudoku-solver%2Fdescription%2F)or[Log in](https://leetcode.com/accounts/login/?next=%2Fproblems%2Fsudoku-solver%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 [37\. Sudoku Solver](https://leetcode.com/problems/sudoku-solver/) Hard Topics Companies Hint Write a program to solve a Sudoku puzzle by filling the empty cells. A sudoku solution must satisfy **all of the following rules**: 1. Each of the digits `1-9` must occur exactly once in each row. 2. Each of the digits `1-9` must occur exactly once in each column. 3. Each of the digits `1-9` must occur exactly once in each of the 9 `3x3` sub-boxes of the grid. The `'.'` character indicates empty cells. **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: [["5","3","4","6","7","8","9","1","2"],["6","7","2","1","9","5","3","4","8"],["1","9","8","3","4","2","5","6","7"],["8","5","9","7","6","1","4","2","3"],["4","2","6","8","5","3","7","9","1"],["7","1","3","9","2","4","8","5","6"],["9","6","1","5","3","7","2","8","4"],["2","8","7","4","1","9","6","3","5"],["3","4","5","2","8","6","1","7","9"]] Explanation: The input board is shown above and the only valid solution is shown below: ``` **Constraints:** - `board.length == 9` - `board[i].length == 9` - `board[i][j]` is a digit or `'.'`. - It is **guaranteed** that the input board has only one solution. Accepted 1,018,909/1.6M Acceptance Rate 65\.4% *** Topics [Array](https://leetcode.com/tag/array/)[Hash Table](https://leetcode.com/tag/hash-table/)[Backtracking](https://leetcode.com/tag/backtracking/)[Matrix](https://leetcode.com/tag/matrix/) ***  Companies *** Hint 1 For each cell, place a valid number and try solving for the remaining empty cells. *** Hint 2 If stuck, undo (backtrack) and try another valid number. *** Similar Questions [Valid Sudoku](https://leetcode.com/problems/valid-sudoku/) Medium [Unique Paths III](https://leetcode.com/problems/unique-paths-iii/) Hard *** Discussion (279) 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 28 Copyright © 2026 LeetCode. All rights reserved. 11\.1K 279 115 Online 1 Ln 1, Col 1 Case 1 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 › \[\["5","3",".",".","7",".",".",".","."\],\["6",".",".","1","9","5",".",".","."\],\[".","9","8",".",".",".",".","6","."\],\["8",".",".",".","6",".",".",".","3"\],\["4",".",".","8",".","3",".",".","1"\],\["7",".",".",".","2",".",".",".","6"\],\[".","6",".",".",".",".","2","8","."\],\[".",".",".","4","1","9",".",".","5"\],\[".",".",".",".","8",".",".","7","9"\]\] Source FindHeaderBarSize FindTabBarSize FindBorderBarSize

Write a program to solve a Sudoku puzzle by filling the empty cells. A sudoku solution must satisfy **all of the following rules**: 1. Each of the digits `1-9` must occur exactly once in each row. 2. Each of the digits `1-9` must occur exactly once in each column. 3. Each of the digits `1-9` must occur exactly once in each of the 9 `3x3` sub-boxes of the grid. The `'.'` character indicates empty cells. **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: [["5","3","4","6","7","8","9","1","2"],["6","7","2","1","9","5","3","4","8"],["1","9","8","3","4","2","5","6","7"],["8","5","9","7","6","1","4","2","3"],["4","2","6","8","5","3","7","9","1"],["7","1","3","9","2","4","8","5","6"],["9","6","1","5","3","7","2","8","4"],["2","8","7","4","1","9","6","3","5"],["3","4","5","2","8","6","1","7","9"]] Explanation: The input board is shown above and the only valid solution is shown below: ``` **Constraints:** - `board.length == 9` - `board[i].length == 9` - `board[i][j]` is a digit or `'.'`. - It is **guaranteed** that the input board has only one solution.