HDU 2222 AC自动机模板题

题目： http://acm.hdu.edu.cn/showproblem.php?pid=2222

AC自动机模板题

我现在对AC自动机的理解还一般，就贴一下我参考学习的两篇博客的链接：

http://blog.csdn.net/niushuai666/article/details/7002823

http://www.cppblog.com/menjitianya/archive/2014/07/10/207604.html

 #include<stdio.h>
 #include<string.h>
 #include<queue>
 using namespace std;
 char key[];
 char des[];
 struct node{
     node *fail;
     node *next[];
     int cnt;
     node(){
         fail = NULL;
         cnt = ;
         for(int i = ;i<;i++)
             next[i] = NULL;
     }
 };
 node *root;
 void insert(char *str){
     node *head = root;
     int len = strlen(str);
     for(int i = ;i<len;i++){
         int temp = str[i]-'a';
         if(head->next[temp] == NULL)
             head->next[temp] = new node();
         head = head->next[temp];
     }
     head->cnt++;
 }
 void build(){
     queue<node *>q;
     q.push(root);
     while(!q.empty()){
         node *head = q.front();
         q.pop();
         for(int i = ;i<;i++){
             if(head->next[i] != NULL){
                 if(head == root){
                     head->next[i]->fail = root;
                 }else{
                     node *temp = head->fail;
                     while(temp != NULL){
                         if(temp->next[i] != NULL){
                             head->next[i]->fail = temp->next[i];
                             break;
                         }
                         temp = temp->fail;
                     }
                     if(temp == NULL)
                         head->next[i]->fail = root;
                 }
                 q.push(head->next[i]);
             }
         }
     }
 }
 int query(){
     int len = strlen(des),ans = ;;
     node *head = root;
     for(int i = ;i<len;i++){
         int index = des[i]-'a';
         while(head->next[index] == NULL && head != root)
             head = head->fail;
         head = head->next[index];
         if(head == NULL)
             head = root;
         node *temp = head;
         while(temp!=root && temp->cnt!=-){
             ans += temp->cnt;
             temp->cnt = -;
             temp = temp->fail;
         }
     }
     return ans;
 }
 int main(){
     int t;
     scanf("%d",&t);
     while(t--){
         root = new node();
         int n;
         scanf("%d",&n);
         for(int i = ;i<n;i++){
             scanf(" %s",key);
             insert(key);
         }
         build();
         scanf(" %s",des);
         printf("%d\n",query());
     }
     return ;
 }