poj 2676 -- Sudoku

 1 /*======================================================================
 2  *           Author :   kevin
 3  *         Filename :   suduku.cpp
 4  *       Creat time :   2014-08-06 15:51
 5  *      Description :
 6  ========================================================================*/
 7 #include <iostream>
 8 #include <algorithm>
 9 #include <cstdio>
10 #include <cstring>
11 #include <queue>
12 #include <cmath>
13 #define clr(a,b) memset(a,b,sizeof(a))
14 #define M 20
15 using namespace std;
16 int s[M][M],row[M][M],col[M][M];
17 /*-------判断是否有3×3格子里是否有b-------*/
18 bool judge(int x,int y,int b)
19 {
20     int i,j;
21     for(i = (x-1)/3*3+1; i <= (x-1)/3*3+3; i++){
22         for(j = (y-1)/3*3+1; j <= (y-1)/3*3+3; j++){
23             if(s[i][j] == b) return false;
24         }
25     }
26     return true;
27 }
28 /*----------------end----------------*/
29 bool DFS(int x,int y) // x代表列，y代表行
30 {
31     if(x == 9 && y == 0){
32         return true;
33     }
34     if(s[y][x]){
35         if(x > 1){
36             if(DFS(x-1,y))
37                 return true;
38         }
39         if(x == 1){
40             if(DFS(9,y-1))
41                 return true;
42         }
43     }
44     else{
45         for(int i = 1; i <= 9; i++){      //枚举1到9
46             if(!row[y][i] && !col[x][i]){ //当前行当前列是否有i
47                 if(judge(y,x,i)){         //判断能否放在3×3方格里
48                     row[y][i] = 1; col[x][i] = 1;
49                     s[y][x] = i;
50                     if(x > 1){
51                         if(DFS(x-1,y)){
52                             return true;
53                         }
54                     }
55                     if(x == 1){
56                         if(DFS(9,y-1)){
57                             return true;
58                         }
59                     }
60                     row[y][i] = 0; col[x][i] = 0;
61                     s[y][x] = 0;
62                 }
63             }
64         }
65     }
66     return false;
67 }
68 int main(int argc,char *argv[])
69 {
70     int n;
71     scanf("%d",&n);
72     getchar();
73     while(n--){
74         clr(s,0);
75         clr(row,0);
76         clr(col,0);
77         char c;
78         for(int i  = 1; i <= 9; i++){
79             for(int j = 1; j <= 9; j++){
80                 scanf("%c",&c);
81                 s[i][j] = c-‘0‘;
82                 row[i][s[i][j]] = 1;   //标记行里出现的数
83                 col[j][s[i][j]] = 1;   //标记列里出现的数
84             }
85             getchar();
86         }
87         DFS(9,9);          //倒着搜
88         for(int i = 1; i <= 9; i++){
89             for(int j = 1; j <= 9; j++){
90                 printf("%d",s[i][j]);
91             }
92             printf("\n");
93         }
94     }
95     return 0;
96 }