洛谷 P1784 数独

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cmath>
 4 #include<cstdlib>
 5 #include<vector>
 6 #include<queue>
 7 #include<stack>
 8 #include<bitset>
 9 #include<iomanip>
10 #include<algorithm>
11 #include<string>
12 #include<cstring>
13 #define inf 100000
14 using namespace std;
15 int t[15][15];
16 bool area[15][15],hang[15][15],lie[15][15];
17 int x,cnt;
18 void dfs(){
19     int cnt=inf,x,y;
20     for (int i=1;i<=9;i++)
21         for (int j=1;j<=9;j++)
22             if(t[i][j]==0)
23             {
24                 int cntt=0;
25                 for (int k=1;k<=9;k++)
26                     if (!hang[i][k]&&!lie[j][k]&&!area[((i+2)/3-1)*3+(j+2)/3][k])
27                         cntt++;
28                 if (cnt>cntt)
29                 {
30                     x=i;
31                     y=j;
32                     cnt=cntt;
33                 }
34             }
35     if (cnt==inf)
36     {
37         for (int i=1;i<=9;i++)
38         {
39             for (int j=1;j<=9;j++)
40             {
41                 printf ("%d ",t[i][j]);
42             }
43             printf ("\n");
44         }
45         exit(0);//here
46     }
47     for (int k=1;k<=9;k++)
48         if (!hang[x][k]&&!lie[y][k]&&!area[((x+2)/3-1)*3+(y+2)/3][k])
49         {
50             hang[x][k]=true;
51             lie[y][k]=true;
52             area[((x+2)/3-1)*3+(y+2)/3][k]=true;
53             t[x][y]=k;
54             dfs();
55             hang[x][k]=false;
56             lie[y][k]=false;
57             area[((x+2)/3-1)*3+(y+2)/3][k]=false;
58             t[x][y]=0;
59         }
60 } 
61 int main (){
62     freopen ("sudoku.in","r",stdin);
63     //freopen ("sudoku.out","w",stdout);
64     for (int i=1;i<=9;i++)
65         for (int j=1;j<=9;j++)
66         {
67             scanf ("%d",&t[i][j]);
68             hang[i][t[i][j]]=true;
69             lie[j][t[i][j]]=true;
70             area[((i+2)/3-1)*3+(j+2)/3][t[i][j]]=true;
71         }
72     dfs();
73     return 0;
74 }