HDU 3065 病毒侵袭持续中（AC自动机)

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解题思路：

跟上一题类似，仍然是AC自动机的简单应用，记录一下每个串出现的次数即可。、

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <vector>
#include <queue>
#include <string.h>
#include <stack>
#include <algorithm>
using namespace std;
char str[1010][60];
struct Trie
{
    int next[1010*50][128],fail[1010*50],end[1010*50];
    int root,L;
    int newnode()
    {
        for(int i = 0;i < 128;i++)
            next[L][i] = -1;
        end[L++] = -1;
        return L-1;
    }
    void init()
    {
        L = 0;
        root = newnode();
    }
    void insert(char buf[], int id)
    {
        int len = strlen(buf);
        int now = root;
        for(int i = 0;i < len;i++)
        {
            if(next[now][buf[i]] == -1)
                next[now][buf[i]] = newnode();
            now = next[now][buf[i]];
        }
        end[now] = id;
    }
    void build()
    {
        queue<int>Q;
        fail[root] = root;
        for(int i = 0;i < 128;i++)
            if(next[root][i] == -1)
                next[root][i] = root;
            else
            {
                fail[next[root][i]] = root;
                Q.push(next[root][i]);
            }
        while( !Q.empty() )
        {
            int now = Q.front();
            Q.pop();
            for(int i = 0;i < 128;i++)
                if(next[now][i] == -1)
                    next[now][i] = next[fail[now]][i];
                else
                {
                    fail[next[now][i]]=next[fail[now]][i];
                    Q.push(next[now][i]);
                }
        }
    }
    int num[1010];
    int query(char buf[],int n)
    {
        int len = strlen(buf);
        int now = root;
        for(int i=1;i<=n;i++)
            num[i] = 0;
        for(int i = 0;i < len;i++)
        {
            now = next[now][buf[i]];
            int temp = now;
            while( temp != root )
            {
                if(end[temp] != -1)
                {
                    num[end[temp]]++;
                }
                temp = fail[temp];
            }
        }
        for(int i=1;i<=n;i++) if(num[i] > 0)
            printf("%s: %d\n", str[i], num[i]);
    }
};
char buf[2000010];
Trie ac;
int main()
{
    int n, m;
    while(scanf("%d", &n)!=EOF)
    {
        ac.init();
        for(int i=1;i<=n;i++)
        {
            scanf("%s", str[i]);
            ac.insert(str[i], i);
        }
        ac.build();
        scanf("%s", &buf);
        ac.query(buf, n);
    }
    return 0;
}

HDU 3065 病毒侵袭持续中（AC自动机)

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原文地址：http://blog.csdn.net/moguxiaozhe/article/details/46932403