题目：给你一些病毒的特征串，再给你一些网站的代码，统计每个网站中出现的病毒和被攻击的网站数。

分析：字符串，AC自动机。数据规模较大，使用 AC自动机。具体参照本站的：AC自动机总结。

说明：开始时把求解 fial合并到 query中了，导致多次 TLE，。。。囧。。。 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int cmp(const void* a, const void* b)
{
    return *((int *)a) - *((int *)b);
}

/* AC_DFA define */
#define nodesize 60006
#define dictsize 128

typedef struct node1
{
    int    flag;
    node1* fail;
    node1* next[dictsize];
}tnode;
tnode  dict[nodesize];
tnode* Q[nodesize];
int    ID[dictsize]; 
int    answer[10001];

class AC_DFA
{
    private:
        int    size;
        tnode* root;
    public:
        AC_DFA() {makeID();init();}
        void makeID() {
            for (int i = 0 ; i < dictsize ; ++ i)
                ID[i] = i;
        }
        void init() {
            memset(dict, 0, sizeof(dict));
            root=NULL;size=0;root=newnode();
        }
        tnode* newnode() {
            dict[size].fail = root;
            return &dict[size ++];
        }
        void insert(char* word, int id) {
            tnode* now = root;
            for (int i = 0 ; word[i] ; ++ i) {
                if (!now->next[ID[word[i]]])
                    now->next[ID[word[i]]] = newnode();
                now = now->next[ID[word[i]]];
            }now->flag = id;
        }
        void setfail() {
            Q[0] = root; root->fail = NULL;
            for (int move = 0,save = 1 ; move < save ; ++ move) {
                tnode* now = Q[move];
                for (int i = 0 ; i < 128 ; ++ i)
                    if (now->next[i]) {
                        tnode* p = now->fail;
                        while (p && !p->next[i]) p = p->fail;
                        now->next[i]->fail = p?p->next[i]:root;
                        Q[save ++] = now->next[i];
                    }else now->next[i] = now==root?root:now->fail->next[i];//构建 Trie图 
            }
        }
        int query(char* line, int id) {
        	int count = 0;
            tnode* now = root;
            for (int i = 0 ; line[i] ; ++ i) {
                now = now->next[ID[line[i]]];
                for (tnode* p = now ; p ; p = p->fail)
                	if (p->flag)
                    	answer[count ++] = p->flag;
            }
            
            if (count) {
                qsort(answer, count, sizeof(int), cmp);
                printf("web %d: %d",id,answer[0]);
                for (int i = 1 ; i < count ; ++ i)
                    if (answer[i] != answer[i-1])
                        printf(" %d",answer[i]);
                printf("\n");
            }
            return count > 0;
        }
};
/* AC_DFA  end */

char Word[205];
char Line[10005];

int main()
{
    int T,N,M,Sum;
    AC_DFA ac;
    scanf("%d",&N);
    for (int i = 1 ; i <= N ; ++ i) {
        scanf("%s",Word);
        ac.insert(Word, i);
    }
    ac.setfail();
    scanf("%d",&M);
    Sum = 0;
    for (int i = 1 ; i <= M ; ++ i ) {
        scanf("%s",&Line);
        Sum += ac.query(Line, i);
    }
    printf("total: %d\n",Sum);
    system("pause");
    return 0;
}

hdu 2896 - 病毒侵袭