Package g0001_0100.s0037_sudoku_solver

Class Solution

  • public class Solution
extends Object
    37 - Sudoku Solver.

    Hard

    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.

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • solveSudoku

        public void solveSudoku​(char[][] board)