Sudoku
Time Limit: 2000 MS Memory Limit: 65536 KB
64-bit integer IO format: %I64d , %I64u Java class name: Main
Special Judge
Description
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
#include<iostream>
#include <string.h>
#include <stdio.h>
using namespace std;
int map[10][10]; //九宫格
bool row[10][10]; //row[i][x] 标记在第i行中数字x是否出现了
bool col[10][10]; //col[j][y] 标记在第j列中数字y是否出现了
bool grid[10][10]; //grid[k][x] 标记在第k个3*3子格中数字z是否出现了
//(这里说明的字母不代表下面程序中的变量)
bool DFS(int x,int y) ///从左到右 上到下
{
if(x==10)
return true;
bool flag=false;
if(map[x][y])
{
if(y==9) ///右边界的列
flag=DFS(x+1,1);
else
flag=DFS(x,y+1);
if(flag) //回溯
return true;
else
return false;
}
else
{
int k=3*((x-1)/3)+(y-1)/3+1;
for(int i=1; i<=9; i++) //枚举数字1~9填空
if(!row[x][i] && !col[y][i] && !grid[k][i])
{
map[x][y]=i;
row[x][i]=true;
col[y][i]=true;
grid[k][i]=true;
if(y==9)
flag=DFS(x+1,1);
else
flag=DFS(x,y+1);
if(!flag) //回溯，继续枚举
{
map[x][y]=0;
row[x][i]=false;
col[y][i]=false;
grid[k][i]=false;
}
else
return true;
}
}
return false;
}
int main()
{
int t;
int i,j;
cin>>t;
while(t--)
{
char MAP[10][10];
for(i=1; i<=9; i++)
{
for(j=1; j<=9; j++)
{
//scanf("%c",&map[i][j]);
cin>>MAP[i][j];
map[i][j]=MAP[i][j]-‘0‘;
}
}
memset(row,false,sizeof(row));
memset(col,false,sizeof(col));
memset(grid,false,sizeof(grid));
for(int i=1; i<=9; i++)
{
for(int j=1; j<=9; j++)
{
if(map[i][j])
{
int k=3*((i-1)/3)+(j-1)/3+1;
row[i][ map[i][j] ]=true;
col[j][ map[i][j] ]=true;
grid[k][ map[i][j] ]=true;
}
}
}
DFS(1,1);
for(i=1; i<=9; i++)
{
for(j=1; j<=9; j++)
printf("%d",map[i][j]);
printf("\n");
}
}
return 0;
}
poj 2676 如何填满九宫格