【HDOJ】2780 Su-Su-Sudoku

模拟+DFS。

 /* 2780 */
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>

 char map[][];
 int visit[][][];
 int fn;
 int fx[], fy[];

 bool dfs(int n) {
     if (n == )
         return true;
     int i = fx[n], j = fy[n], k, r;

     for (k=; k<=; ++k) {
         if (!visit[i][j][k]) {
             map[i][j] = k;
             visit[i][j][k]++;
             for (r=; r<; ++r) {
                 visit[i][r][k]++;
                 visit[r][j][k]++;
                 visit[i/*+k/][j/*+k%][k]++;
             }
             if (dfs(n-))
                 return true;
             visit[i][j][k]--;
             for (r=; r<; ++r) {
                 visit[i][r][k]--;
                 visit[r][j][k]--;
                 visit[i/*+k/][j/*+k%][k]--;
             }
         }
     }
     return false;
 }

 bool check() {
     int i, j, k;
     int x, y, in;
     bool f[];

     // check row
     for (i=; i<; ++i) {
         memset(f, false, sizeof(f));
         for (j=; j<; ++j) {
             if (map[i][j] && f[map[i][j]]) {
                 return true;
             }
             f[map[i][j]] = true;
         }
     }

     // check line
     for (j=; j<; ++j) {
         memset(f, false, sizeof(f));
         for (j=; j<; ++j) {
             if (map[i][j] && f[map[i][j]]) {
                 return true;
             }
             f[map[i][j]] = true;
         }
     }

     // check sub
     for (x=; x<; ++x) {
         memset(f, false, sizeof(f));
         for (y=; y<; ++y) {
             i = x/* + y/;
             j = x%* + y%;
             if (map[i][j] && f[map[i][j]]) {
                 return true;
             }
             f[map[i][j]] = true;
         }
     }

     return false;
 }

 int main() {
     int t;
     int i, j, k;
     bool flag;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d", &t);
     while (t--) {
         memset(visit, , sizeof(visit));
         fn = ;
         for (i=; i<; ++i) {
             scanf("%s", map[i]);
             for (j=; j<; ++j) {
                 map[i][j] -= '';
                 if (map[i][j] == ) {
                     fx[fn] = i;
                     fy[fn] = j;
                     ++fn;
                 } else {
                     for (k=; k<; ++k) {
                         visit[i][k][map[i][j]]++;
                         visit[k][j][map[i][j]]++;
                         visit[i/*+k/][j/*+k%][map[i][j]]++;
                     }
                 }
             }
         }
         if (check()) {
             flag = false;
         } else {
             flag = dfs();
         }
         if (flag) {
             for (i=; i<; ++i) {
                 for (j=; j<; ++j)
                     map[i][j] += '';
                 puts(map[i]);
             }
         } else {
             puts("Could not complete this grid.");
         }
         if (t)
             printf("\n");
     }

     return ;
 }