2580 스토쿠

import java.util.Scanner;

class stoku {

    Scanner sc1 = new Scanner(System.in);
    int[][] board = new int[9][9];
    boolean[][] row = new boolean[9][10];
    boolean[][] col = new boolean[9][10];
    boolean[][] square = new boolean[9][10] ;
    boolean pri;

    public void insert(){
        for(int i=0; i<9 ;i++){
            for(int j=0; j<9 ;j++) {
                board[i][j]=sc1.nextInt();

                switch (board[i][j]){
                    case 1: row[i][1] = true; col[j][1] = true; square[(i/3)*3+(j/3)][1] = true; break;
                    case 2: row[i][2] = true; col[j][2] = true; square[(i/3)*3+(j/3)][2] = true; break;
                    case 3: row[i][3] = true; col[j][3] = true; square[(i/3)*3+(j/3)][3] = true; break;
                    case 4: row[i][4] = true; col[j][4] = true; square[(i/3)*3+(j/3)][4] = true; break;
                    case 5: row[i][5] = true; col[j][5] = true; square[(i/3)*3+(j/3)][5] = true; break;
                    case 6: row[i][6] = true; col[j][6] = true; square[(i/3)*3+(j/3)][6] = true; break;
                    case 7: row[i][7] = true; col[j][7] = true; square[(i/3)*3+(j/3)][7] = true; break;
                    case 8: row[i][8] = true; col[j][8] = true; square[(i/3)*3+(j/3)][8] = true; break;
                    case 9: row[i][9] = true; col[j][9] = true; square[(i/3)*3+(j/3)][9] = true; break;
                }
            }
        }
    }

    public boolean hasZero() {
        for (int i = 0; i < 9; i++) {
            for (int j = 0; j < 9; j++) {
                if(board[i][j] == 0) {
                    return true;
                }
            }
        }
        pri = true;
        return false;
    }

    public void start() {
        for (int i = 0; i <9; i++) {
            for (int j = 0; j < 9; j++) {
                if(board[i][j] == 0) {
                    for (int k = 1; k <= 9; k++) {
                        if ((!row[i][k]) && (!col[j][k]) && (!square[(i / 3) * 3 + (j / 3)][k]) ) {
                            board[i][j] = k;
                            row[i][k] = true;
                            col[j][k] = true;
                            square[(i / 3) * 3 + (j / 3)][k] = true;
                            if (!hasZero())return;

                            start();

                            if(!pri){
                            board[i][j] = 0;
                            row[i][k] = false;
                            col[j][k] = false;
                            square[(i / 3) * 3 + (j / 3)][k] = false;
                        }
                        }
                    }
                }
                    }
                }
        }


//출력
    public void getBoard(){
        for(int i=0; i<9 ;i++){
            for(int j=0; j<9 ;j++) {
                System.out.printf("%d ",board[i][j]);
            }
            System.out.println();
        }
    }


}


public class _2580{
    public static void main(String[] args) {
        stoku s1 = new stoku();
        s1.insert();

        s1.start();

        s1.getBoard();
    }
}