HDU 2896：病毒侵袭（AC自动机）

http://acm.hdu.edu.cn/showproblem.php?pid=2896

题意：中文题意。

思路：AC自动机模板题。主要在于字符有128种，输出还要排序和去重！

注意是“total”不是“totol”！！！因为这个Debug了好久。

还有结点是new的，不然MLE。

主要用来测试模板，看了两个，发现没有注释掉的效率高点。

 #include <cstring>
 #include <algorithm>
 #include <cstdio>
 #include <vector>
 #include <queue>
 using namespace std;
 #define N 100010
 #define TOL 128

 typedef struct Node {
     Node* next[TOL];
     Node* fail;
     int id;
     Node() {
         for(int i = ; i < TOL; i++) next[i] = NULL;
         fail = NULL; id = ;
     }
 } node;

 class AC_DFA {

     private:
         int ans;
         node *root;

     public:
         AC_DFA() {
             ans = ; root = new Node();
         }

         void insert(char* s, int id) {
             node* now = root;
             int len = strlen(s);
             for(int i = ; i < len; i++) {
                 char c = s[i];
                 if(now->next[c] == NULL) now->next[c] = new Node();
                 now = now->next[c];
             }
             now->id = id;
         }

         void build() {
             root->fail = NULL;
             queue<node*> que;
             que.push(root);
             while(!que.empty()) {
                 node* now = que.front(); que.pop();
                 for(int i = ; i < TOL; i++) {
                     if(now->next[i]) {
                         node* p = now->fail;
                         while(p && p->next[i] == NULL) p = p->fail;
                         if(p) now->next[i]->fail = p->next[i];
                         else now->next[i]->fail = root;
                         que.push(now->next[i]);
                     } else {
                         if(now == root) now->next[i] = root;
                         else now->next[i] = now->fail->next[i];
                     }
                 }
             }
         }

         void match(char *s, int id) {
             bool flag = ;
             int len = strlen(s);
             vector<int> tol;
             node* now = root; node* p;
             for(int i = ; i < len; i++) {
                 char c = s[i];
                 while(now->next[c] == NULL && now != root) now = now->fail;
                 now = now->next[c];
                 p = now;
                 while(p) {
                     if(p->id) tol.push_back(p->id), flag = ;
                     p = p->fail;
                 }
                 /*
                 char c = s[i];
                 now = now->next[c];
                 p = now;
                 while(p) {
                     if(p->id) tol.push_back(p->id), flag = 1;
                     p = p->fail;
                 }
                 */
             }

             if(!flag) return ;
             sort(tol.begin(), tol.end());
             int cnt = unique(tol.begin(), tol.end()) - tol.begin(); // 去重
             ans++;
             printf("web %d: ", id);
             for(int i = ; i < cnt; i++) {
                 printf("%d", tol[i]);
                 if(i == cnt - ) putchar('\n');
                 else putchar(' ');
             }
         }

         void print() {
             printf("total: %d\n", ans); // 不是totol
         }

 };

 int main() {

     AC_DFA ac;
     char s[];
     int n; scanf("%d", &n);
     for(int i = ; i <= n; i++) {
         scanf("%s", s); ac.insert(s, i);
     }
     ac.build();
     int m; scanf("%d", &m);
     for(int i = ; i <= m; i++) {
         scanf("%s", s); ac.match(s, i);
     }
     ac.print();
     return ;
 }