POJ 2676 Sudoku 数独（枚举dfs）

Sudoku is a very simple task. A square table with 9 rows and 9 columns is divided to 9 smaller squares 3x3 as shown on the Figure. In some of the cells are written decimal digits from 1 to 9. The other cells are empty. The goal is to fill the empty cells with decimal digits from 1 to 9, one digit per cell, in such way that in each row, in each column and in each marked 3x3 subsquare, all the digits from 1 to 9 to appear. Write a program to solve a given Sudoku-task. 

Input

The input data will start with the number of the test cases. For each test case, 9 lines follow, corresponding to the rows of the table. On each line a string of exactly 9 decimal digits is given, corresponding to the cells in this line. If a cell is empty it is represented by 0.

Output

For each test case your program should print the solution in the same format as the input data. The empty cells have to be filled according to the rules. If solutions is not unique, then the program may print any one of them.

Sample Input

1
103000509
002109400
000704000
300502006
060000050
700803004
000401000
009205800
804000107

Sample Output

143628579
572139468
986754231
391542786
468917352
725863914
237481695
619275843
854396127

数独问题：

       给你一个9*9的方格，要求每行每列的9个数字都不相同，然后将这方格，分成9个3*3的小方格，要求每个小方格里面的数字也都不相同。现在给你一些数字，0代表你要添加的数字，使其形成一个数独。

思路：枚举9个数字+dfs深搜，注意输入，每一行都是一个数，不能一个数字一个数字写入，只能是一个字符一个字符写入

代码：

    

#include
#include
using namespace std;
int g[10][10];
int vis[100][2];//记录未知数的位置  
int num;        //记录未知数的总个数 

//同一行同一列同一九宫格不能相同 
int judge(int x,int y,int k)
{
	for(int i=0;i<9;i++)
	{
		if(g[i][y]==k) return 0;
		if(g[x][i]==k) return 0;
	}
	int xx=(x/3)*3;
	int yy=(y/3)*3;
	for(int i=0;i<3;i++)
	for(int j=0;j<3;j++)
	{
		if(g[i+xx][j+yy]==k)
		   return 0;
	} 
	return 1;
}

//对num个未知数进行枚举dfs判断 
int dfs(int idx)
{
	if(idx<0) return 1;
	for(int i=1;i<=9;i++)
	{
		int x=vis[idx][0];
		int y=vis[idx][1];
		if(judge(x,y,i))
		{
			g[x][y]=i;
			if(dfs(idx-1)) return 1;
			g[x][y]=0;
		} 
	} 
	return 0;
}

int main()
{
	int t;
	cin>>t;
	while(t--)
	{
	    char c;
	   	num=0;
	    for(int i=0;i<9;i++)
	    for(int j=0;j<9;j++)
	    {
	   	    scanf(" %c",&c);
	   	    g[i][j]=c-'0';
	   	    if(g[i][j]==0)
	   	    {
	   	   	    vis[num][0]=i;
	   	   	    vis[num++][1]=j;
			}
	   	   
		}
		
		dfs(num-1);
		
		for(int i=0;i<9;i++)
		{
			for(int j=0;j<9;j++)
			  cout<