hdu 6208 The Dominator of Strings【AC自动机】

hdu 6208 The Dominator of Strings【AC自动机】

求一个串包含其他所有串，找出最长串去匹配即可，但是匹配时要对走过的结点标记，不然T死QAQ，，扎心了。。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<queue>
 using namespace std;
 inline void read(int&a){char c;while(!(((c=getchar())>='')&&(c<='')));a=c-'';while(((c=getchar())>='')&&(c<=''))(a*=)+=c-'';}
 const int N = ;
 const int M = ;
 struct Trie {
     int next[N][M], fail[N], tag[N];
     int root;
     int vis[N];
     int L;
     int newnode() {
         for(int i = ;i < M;i++)
             next[L][i] = -;
         vis[L] = ;
         tag[L++] = ;

         return L-;
     }
     void init() {
         L = ;
         root = newnode();
     }
     void Insert(char buf[]) {
         int len = strlen(buf);
         int u = root;
         for(int i = ; i < len; i++) {
             if(next[u][buf[i]-'a'] == -)
                 next[u][buf[i]-'a'] = newnode();
             u = next[u][buf[i]-'a'];
         }
         tag[u]++;
     }
     void build() {
         queue<int> Q;
         fail[root] = root;
         for(int i = ; i < M; i++) {
             if(next[root][i] == -)
                 next[root][i] = root;
             else {
                 fail[next[root][i]] = root;
                 Q.push(next[root][i]);
             }
         }
         while( !Q.empty() ) {
             int u = Q.front();
             Q.pop();
             for(int i = ; i < M; i++) {
                 int &v = next[u][i];
                 if(v == -)
                     v = next[fail[u]][i];
                 else {
                     Q.push(v);
                     fail[v] = next[fail[u]][i];
                 }
             }
         }
     }
     int query(char buf[]) {
         int len = strlen(buf);
         int u = root;
         int res = ;
         for(int i = ; i < len; i++) {
             u = next[u][buf[i]-'a'];
             int t = u;
             while( t != root && !vis[t] ) {
                 res += tag[t];

                 vis[t] = ;//要不然会t啊

                 tag[t] = ;
                 t = fail[t];

             }
         }
         return res;
     }
 };
 char s[N];
 char ss[N];
 Trie ac;
 int main() {
     int t, n;
     read(t);
     while(t--){
         int ma = ;
         ac.init();
         read(n);

         for(int i=; i<n; i++){
             scanf("%s",s);
             int len = strlen(s);
             ac.Insert(s);
             if(ma <= len){
                 ma = len; strcpy(ss, s);
             }
         }
         ac.build();
         int ans = ac.query(ss);
         if(ans == n){
             printf("%s\n",ss);
         }
         else printf("No\n");
     }
     return ;
 }

2168MS