Package g0001_0100.s0036_valid_sudoku

Class Solution

java.lang.Object
g0001_0100.s0036_valid_sudoku.Solution
public class Solution extends java.lang.Object
36 - Valid Sudoku.

Medium

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 '.'.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    isValidSudoku(char[][] board)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • isValidSudoku

      public boolean isValidSudoku(char[][] board)