hihoCoder#1048 状态压缩·二

原题地址

位运算的状态压缩太操蛋了，很容易出错。。。又是数组没开够导致诡异现象（明明某个值是1，莫名其妙就变成0了），害我debug一整天！fuck

代码：

 #include <iostream>
 #include <cstring>

 using namespace std;

 #define MAX_N 1024
 #define MAX_M 8
 #define MAX_S 4096
 #define MOD 1000000007

 int f[MAX_N][MAX_M][MAX_S];
 int N, M;

 bool freep(int s, int o) {
   return !(s & ( << o));
 }

 int mark(int s, int o) {
   return s |= ( << o);
 }

 int mark(int s, int o1, int o2) {
   return mark(s, o1) | mark(s, o2);
 }

 int main() {
   cin >> N >> M;
   memset(f, , sizeof(f));

   for (int i = ; i <= N; i++) {
     for (int s = ; s < ( << ( * M + )); s++)
       f[i][M + ][s] = ;
   }
   for (int j = ; j <= M; j++) {
     for (int s = ; s < ( << ( * M + )); s++)
       f[N + ][j][s] = ;
   }

   for (int i = N; i >= ; i--) {
     for (int j = M; j >= ; j--) {
       for (int k = ( << ( * M)) - ; k >= ; k--) {
         int s = k << ;
         // pass
         if (!freep(s, j)) {
           if (j < M)
             f[i][j][s] = f[i][j + ][s];
           if (j == M)
             f[i][j][s] = f[i + ][][(s >> M) >>  << ];
         }
         if (freep(s, j)) {
           // impossible
           if ((j == M || !freep(s, j + )) && (i == N || !freep(s, j + M)))
             f[i][j][s] = ;
           // right
           if (j < M && freep(s, j + ) && (i == N || !freep(s, j + M)))
             f[i][j][s] += f[i][j][mark(s, j, j + )];
           // down
           if (i < N && freep(s, j + M) && (j == M || !freep(s, j + )))
             f[i][j][s] += f[i][j][mark(s, j, j + M)];
           // right & down
           if (j < M && freep(s, j + ) && i < N && freep(s, j + M))
             f[i][j][s] = (f[i][j][mark(s, j, j + )] + f[i][j][mark(s, j, j + M)]) % MOD;
         }
       }
     }
   }

   cout << f[][][] << endl;

   return ;
 }