【HDOJ】1818 It's not a Bug, It's a Feature!

状态压缩+优先级bfs。

 /* 1818 */
 #include <iostream>
 #include <queue>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 #include <algorithm>
 using namespace std;

 #define MAXM 105

 typedef struct {
     int t;
     int bm, bp;    // before minus/plus
     int am, ap; // after minus/plus
 }  patch_t;

 typedef struct node_t {
     int v, t;
     node_t() {}
     node_t(int vv, int tt) {
         v = vv; t = tt;
     }
     friend bool operator <(const node_t &a, const node_t &b) {
         return a.t > b.t;
     }
 } node_t;

 int n, m;
 patch_t patch[MAXM];
 int visit[<<];
 char bs[], as[];

 int bfs() {
     int i, j, k;
     int v, t;
     node_t nd = node_t((<<n)-, );
     priority_queue<node_t> Q;

     memset(visit, 0x3f, sizeof(int)*(<<n));
     visit[nd.v] = ;
     Q.push(nd);

     while (!Q.empty()) {
         nd = Q.top();
         if (nd.v == )
             return nd.t;
         Q.pop();
         for (i=; i<m; ++i) {
             v = nd.v;
             if ((v&patch[i].bm)!= || (v&patch[i].bp)!=patch[i].bp)
                 continue;
             v |= patch[i].ap;
             v &= (~patch[i].am);
             t = nd.t + patch[i].t;
             if (t < visit[v]) {
                 Q.push(node_t(v, t));
                 visit[v] = t;
             }
         }
     }

     return -;
 }

 int main() {
     int t = ;
     int i, j, k;

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

     while (scanf("%d%d",&n,&m)!=EOF && (n||m)) {
         for (i=; i<m; ++i) {
             scanf("%d %s %s", &patch[i].t, bs, as);
             patch[i].bp = patch[i].bm = patch[i].ap = patch[i].am = ;
             // handle before str
             for (j=; j<n; ++j) {
                 if (bs[j] == '+')
                     patch[i].bp |= ( << (n--j));
                 else if (bs[j] == '-')
                     patch[i].bm |= ( << (n--j));

             }
             // handle after str
             for (j=; j<n; ++j) {
                 if (as[j] == '+')
                     patch[i].ap |= ( << (n--j));
                 else if (as[j] == '-')
                     patch[i].am |= ( << (n--j));

             }
         }
         k = bfs();
         if (k < )
             printf("Product %d\nBugs cannot be fixed.\n\n", ++t);
         else
             printf("Product %d\nFastest sequence takes %d seconds.\n\n", ++t, k);
     }

     return ;
 }