Aho-Corasick automaton 模板

typedef struct Node* node;const int MAXNs = ;//模式串最大長度 
const int MAXNS = ;//文章（待匹配串）最大長度 struct Node{node next[26];node fail;//失配指针int sum;Node(){sum = 0;fail = NULL;memset(next,NULL,sizeof next);}
};char s[MAXNs];//模式串void Insert(node root)//字典树的建立
{node p = root;int len = strlen(s);for(int i=0 ; i<len ; ++i){int x = s[i] - 'a';if(p->next[x] == NULL){node newnode = new Node();p->next[x] = newnode;}p = p->next[x];}p->sum++;
}void build_fail_pointer(node root)//构造fail指针
{queue<node> Q;Q.push(root);node p,temp;while(!Q.empty()){temp = Q.front();Q.pop();for(int i=0 ; i<26 ; ++i){if(temp->next[i]){if(temp == root){temp->next[i]->fail = root;}else{p = temp->fail;while(p){if(p->next[i]){temp->next[i]->fail = p->next[i];break;}p = p->fail;}if(p == NULL) temp->next[i]->fail = root;}Q.push(temp->next[i]);}}}
}char S[MAXNS];//文章（待匹配串）int ac_automation(node root)//利用fail指针进行匹配。
{node p = root;int len = strlen(S);int ans = 0;for(int i=0 ; i<len ; ++i){int x = S[i] - 'a';while(!p->next[x] && p != root) p = p->fail;p = p->next[x];if(!p) p = root;node temp = p;while(temp != root){if(temp->sum >= 0){ans += temp->sum;temp->sum = -1;}else break;temp = temp->fail;}}return ans;
}void Del(node root){for(int i=0 ; i<26 ; ++i){if(root->next[i])Del(root->next[i]);}delete(root);
}int main(){int T;// case數量 scanf("%d",&T);while(T--){int N;//模式串數量 node root = new Node();scanf("%d",&N);while(N--){scanf("%s",s);Insert(root);}scanf("%s",S);build_fail_pointer(root);//构造fail指针printf("%d\n",ac_automation(root));Del(root);}return 0;
}