/**
 * 
 */
package com.test;

public class ShuDu {
	static boolean next(int[][] n, int i, int j) {
		// 寻找需填充的格子
		while (n[i][j] != 0) {
			if (j < 8)
				j++;
			else if (i < 8) {
				i++;
				j = 0;
			} else {
				// 填充完毕
				return true;
			}
		}
		// 填充尝试
		for (int k = 1; k <= 9; k++) {
			n[i][j] = k;
			if (status(n, i, j)) {
				if (!next(n, i, j))
					continue;
				return true;
			}
		}
		n[i][j] = 0; // 都不满足，退回上一步
		return false;
	}

	static boolean status(int[][] n, int i, int j) {
		int s = n[i][j];
		// 判断同列
		for (int k = 0; k < 9; k++) {
			if (k == j)
				continue;
			if (n[i][k] == s)
				return false;
		}
		// 判断同行
		for (int k = 0; k < 9; k++) {
			if (k == i)
				continue;
			if (n[k][j] == s)
				return false;
		}
		// 判断同在一个九格的情况
		int bi = i / 3 * 3;
		int bj = j / 3 * 3;
		for (int ii = bi; ii < bi + 3; ii++) {
			for (int jj = bj; jj < bj + 3; jj++) {
				if (ii == i && jj == j)
					continue;
				if (n[ii][jj] == n[i][j])
					return false;
			}
		}
		return true;
	}

	static void print(int[][] n) {
		for (int i = 0; i < 9; i++) {
			for (int j = 0; j < 9; j++) {
				System.out.print(n[i][j] + " ");
			}
			System.out.println();
		}
		System.out.println();
	}

	public static void main(String[] args) {
		int[][] n = { { 8, 0, 0, 0, 0, 0, 0, 0, 0 },
				{ 0, 0, 3, 6, 0, 0, 0, 0, 0 }, { 0, 7, 0, 0, 9, 0, 2, 0, 0 },
				{ 0, 5, 0, 0, 0, 7, 0, 0, 0 }, { 0, 0, 0, 0, 4, 5, 7, 0, 0 },
				{ 0, 0, 0, 1, 0, 0, 0, 3, 0 }, { 0, 0, 1, 0, 0, 0, 0, 6, 8 },
				{ 0, 0, 8, 5, 0, 0, 0, 1, 0 }, { 0, 9, 0, 0, 0, 0, 4, 0, 0 } };
		print(n);
		next(n, 0, 0);
		print(n);
	}
}