package question;

/*
 @author: Roderland
 @create: 2020年09月15日---15:39
*/
public class Question37 {

 public static void main(String[] args) {
 System.out.println('9'-'0');
 }

 boolean[][] row = new boolean[9][9];
 boolean[][] column = new boolean[9][9];
 boolean[][][] grid = new boolean[3][3][9];

 public void solveSudoku(char[][] board) {
 for (int i = 0; i < board.length; i++) {
 for (int j = 0; j < board[i].length; j++) {
 if (board[i][j]!='.') {
 row[i][board[i][j]-'1']=true;
 column[j][board[i][j]-'1']=true;
 grid[i/3][j/3][board[i][j]-'1']=true;
 }
 }
 }
 fun(board);
 }

 public boolean fun(char[][] board) {
 for (int i = 0; i < board.length; i++) {
 for (int j = 0; j < board[i].length; j++) {
 if (board[i][j]=='.') {
 for (int k = 0; k < 9; k++) {
 if (row[i][k]||column[j][k]||grid[i/3][j/3][k]) continue;
 row[i][k]=true;
 column[j][k]=true;
 grid[i/3][j/3][k]=true;
 board[i][j]=String.valueOf(k+1).toCharArray()[0];
 if (!fun(board)) {
 row[i][k]=false;
 column[j][k]=false;
 grid[i/3][j/3][k]=false;
 board[i][j]='.';
 }
 }
 if (board[i][j]=='.') return false;
 }
 }
 }
 return true;
 }
}