poj2676Sudoku

http://poj.org/problem?id=2676

一列一列的放 判断是否符合条件

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  1 #include <iostream>

  2 #include<cstdio>

  3 #include<cstring>

  4 #include<stdlib.h>

  5 using namespace std;

  6 char s[20][20];

  7 int vx[20][20],vy[20][20],vis[20][20];

  8 int judge(int x,int y)

  9 {

 10     if(x>=0&&x<3&&y>=0&&y<3)

 11        return 1;

 12     if(x>=0&&x<3&&y>=3&&y<6)

 13        return 2;

 14     if(x>=0&&x<3&&y>=6&&y<9)

 15        return 3;

 16     if(x>=3&&x<6&&y>=0&&y<3)

 17        return 4;

 18     if(x>=3&&x<6&&y>=3&&y<6)

 19        return 5;

 20     if(x>=3&&x<6&&y>=6&&y<9)

 21        return 6;

 22     if(x>=6&&x<9&&y>=0&&y<3)

 23        return 7;

 24     if(x>=6&&x<9&&y>=3&&y<6)

 25        return 8;

 26     if(x>=6&&x<9&&y>=6&&y<9)

 27        return 9;

 28 }

 29 int dfs(int x,int y)

 30 {

 31     int kk=0,k;

 32     if(x==9)

 33         return 1;

 34     if(s[x][y]!='0')

 35     {

 36         if(y==8)

 37             kk = dfs(x+1,0);

 38         else

 39             kk = dfs(x,y+1);

 40         if(kk)

 41             return 1;

 42         else

 43             return 0;

 44     }

 45     else

 46     {

 47         for(k = 1; k <= 9 ; k++)

 48         {

 49             if(!vx[x][k]&&!vy[y][k]&&!vis[judge(x,y)][k])

 50             {

 51                 vx[x][k] = 1;

 52                 vy[y][k] = 1;

 53                 vis[judge(x,y)][k] = 1;

 54                 s[x][y] = k+'0';

 55                 if(y==8)

 56                    kk = dfs(x+1,0);

 57                 else

 58                    kk = dfs(x,y+1);

 59                 if(kk)

 60                    return 1;

 61                 else

 62                 {

 63                     s[x][y] = '0';

 64                     vx[x][k] = 0;

 65                     vy[y][k] = 0;

 66                     vis[judge(x,y)][k] = 0;

 67                 }

 68             }

 69         }

 70     }

 71     return 0;

 72 }

 73 int main()

 74 {

 75     int i,j,t;

 76     cin>>t;

 77     while(t--)

 78     {

 79         memset(vx,0,sizeof(vx));

 80         memset(vy,0,sizeof(vy));

 81         memset(vis,0,sizeof(vis));

 82         getchar();

 83         for(i = 0 ; i < 9 ; i++)

 84             for(j = 0 ; j < 9 ; j++)

 85                 {

 86                     cin>>s[i][j];

 87                     if(s[i][j]!='0')

 88                     {

 89                         vx[i][s[i][j]-'0'] = 1;

 90                         vy[j][s[i][j]-'0'] = 1;

 91                         vis[judge(i,j)][s[i][j]-'0'] = 1;

 92                     }

 93                 }

 94         if(dfs(0,0))

 95         {

 96             for(i = 0 ; i < 9 ; i++)

 97             {

 98                 for(j = 0 ; j < 9 ;j++)

 99                 cout<<s[i][j];

100                 puts("");

101             }

102         }

103         else

104         puts("fdg");

105     }

106     return 0;

107 }