【HDOJ】2222 Keywords Search

AC自动机基础题。

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 #include <queue>
 using namespace std;

 #define MAXL  1000005
 #define TRIEN 26

 char des[MAXL], src[];

 typedef struct Trie {
     int n;
     Trie *fail;
     Trie *next[TRIEN];
     Trie () {
         n = ;
         fail = NULL;
         memset(next, , sizeof(next));
     }
 } Trie;

 Trie *root;
 int n;

 void create(char str[]) {
     int i=, id;
     Trie *p = root, *q;

     while (str[i]) {
         id = str[i] - 'a';
         ++i;
         if (p->next[id] == NULL) {
             q = new Trie();
             p->next[id] = q;
         }
         p = p->next[id];
     }
     p->n++;
 }

 void build_fail() {
     int i;
     Trie *p, *q;
     queue<Trie *> que;

     for (i=; i<TRIEN; ++i) {
         if (root->next[i]) {
             root->next[i]->fail = root;
             que.push(root->next[i]);
         }
     }

     while (!que.empty()) {
         p = que.front();
         que.pop();
         for (i=; i<TRIEN; ++i) {
             if (p->next[i]) {
                 q = p->fail;
                 while (q != NULL) {
                     if (q->next[i]) {
                         p->next[i]->fail = q->next[i];
                         break;
                     }
                     q = q->fail;
                 }
                 if (q == NULL)
                     p->next[i]->fail = root;
                 que.push(p->next[i]);
             }
         }
     }
 }

 void search() {
     int i = , id;
     Trie *p = root, *tmp;

     n = ;

     while (des[i]) {
         id = des[i] - 'a';
         ++i;
         while (p->next[id]==NULL && p!=root)
             p = p->fail;
         p = p->next[id];
         if (p == NULL)
             p = root;
         tmp = p;
         while (tmp != root) {
             n += tmp->n;
             tmp->n = ;
             tmp = tmp->fail;
         }
     }
 }

 void del(Trie *t) {
     if (t == NULL)
         return ;
     for (int i=; i<TRIEN; ++i)
         del(t->next[i]);
     free(t);
 }

 int main() {
     int case_n;

     scanf("%d", &case_n);
     while (case_n--) {
         scanf("%d", &n);
         root = new Trie();
         while (n--) {
             scanf("%s", src);
             create(src);
         }
         scanf("%s", des);
         build_fail();
         search();
         printf("%d\n", n);
         del(root);
     }

     return ;
 }