【HDOJ】2589 正方形划分

暴力DFS

 /* 2589 */
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>

 #define MAXN 21

 bool map[MAXN][MAXN];
 bool visit[MAXN][MAXN];
 int l, n;

 bool dfs(int cnt) {
     int i, j, k;
     int x, y, r;
     int ex, ey;
     bool flag = true;

     for (x=; x<=l; ++x) {
         for (y=; y<=l; ++y) {
             if (!visit[x][y]) {
                 flag = false;
                 break;
             }
         }
         if (flag == false)
             break;
     }
     if (flag) {
         if (cnt == )
             return true;
         else
             return false;
     }
     flag = true;
     for (r=; flag&&r<l; ++r) {
         ex = x + r;
         ey = y + r;
         if (ex>l || ey>l)
             break;
         k = ;
         for (i=x; i<=ex; ++i) {
             for (j=y; j<=ey; ++j) {
                 if (map[i][j])
                     ++k;
                 if (k> || visit[i][j]) {
                     flag = false;
                     break;
                 }
             }
             if (flag == false)
                 break;
         }
         if (k== && flag) {
             for (i=x; i<=ex; ++i)
                 for (j=y; j<=ey; ++j)
                     visit[i][j] = true;
             if (dfs(cnt - ))
                 return true;
             for (i=x; i<=ex; ++i)
                 for (j=y; j<=ey; ++j)
                     visit[i][j] = false;
         }
     }
     return false;
 }

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

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

     scanf("%d", &t);
     while (t--) {
         scanf("%d %d", &l, &n);
         memset(map, false, sizeof(map));
         memset(visit, false, sizeof(visit));
         flag = true;
         for (i=; i<n; ++i) {
             scanf("%d %d", &j, &k);
             if (map[j][k])
                 flag = false;
             map[j][k] = true;
         }
         if (flag) {
             flag = dfs(n);
         }
         if (flag)
             puts("YES");
         else
             puts("NO");
     }

     return ;
 }