【AC自动机】 HDOJ 3065 病毒侵袭持续中

AC自动机模板题。。因为没有理解昀神的思想，花了好久。。。

#include <iostream>
#include <sstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <climits>
#define maxn 2000005
#define eps 1e-6
#define mod 10007
#define INF 99999999
#define lowbit(x) (x&(-x))
//#define lson o<<1, L, mid
//#define rson o<<1 | 1, mid+1, R
typedef long long LL;
using namespace std;

int next[maxn][26];
int fail[maxn];
int end[maxn];
queue<int> q;
char str[1005][60];
char t[maxn];
int cnt[maxn];
int top;
int root, tmp, now;
int n;

int newnode(void)
{
	fail[top] = end[top] = -1;
	for(int i = 0; i < 26; i++)
		next[top][i] = -1;
	return top++;
}
void init(void)
{
	top = 0;
	memset(cnt, 0, sizeof cnt);
	root = newnode();
}
void insert(char *s, int x)
{
	int len = strlen(s), i, k;
	now = root;
	for(i = 0; i < len; i++) {
		k = s[i] - 'A';
		if(next[now][k] == -1) next[now][k] = newnode();
		now = next[now][k];
	}
	end[now] = x;
}
void build(void)
{
	
	int i;
	fail[root] = root;
	for(i = 0; i < 26; i++) {
		if(~next[root][i]) {
			fail[next[root][i]] = root;
			q.push(next[root][i]);
		}
		else next[root][i] = root;
	}
	while(!q.empty()) {
		now = q.front();
		q.pop();
		for(i = 0; i < 26; i++) {
			if(~next[now][i]) {
				fail[next[now][i]] = next[fail[now]][i];
				q.push(next[now][i]);
			}
			else next[now][i] = next[fail[now]][i];
		}
	}
}
void read(void)
{
	for(int i = 1; i <= n; i++) {
		scanf("%s", str[i]);
		insert(str[i], i);
	}
	scanf("%s", t);
}
void query(void)
{
	int len = strlen(t), i;
	now = root;
	for(i = 0; i < len; i++) {
		if(t[i] < 'A' || t[i] > 'Z'){
			now = root;
			continue;
		}
		now = next[now][t[i] - 'A'];
		tmp = now;
		while(tmp != root) {
			if(~end[tmp]) cnt[end[tmp]]++;
			tmp = fail[tmp];
		}
	}
}
void work(void)
{
	for(int i = 1; i <= n; i++)
		if(cnt[i])
			printf("%s: %d\n", str[i], cnt[i]);
}
int main(void)
{
	while(scanf("%d", &n)!=EOF) {
		init();
		read();
		build();
		query();
		work();
	}
	return 0;
}