HDOJ 2896 病毒侵袭（AC自动机入门）

题意：

求感染病毒的网站，并输出其感染的病毒特征码编号。

思路：

AC自动机入门，思路同 HDOJ 2222

#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;

const int MAX_NODE = 500 * 200 + 10;
const int CHILD_NUM = 128;

class AcAutomaton
{
private:
    int size;
    int trie[MAX_NODE][CHILD_NUM];
    int fail[MAX_NODE];
    int value[MAX_NODE];
    int table[CHILD_NUM];
    bool visit[MAX_NODE];

public:
    void Initialize()
    {
        fail[0] = 0;
        for (int i = 0; i < CHILD_NUM; ++i)
            table[i] = i;
    }

    void Reset()
    {
        size = 1;
        memset(trie[0], 0, sizeof(trie[0]));
        memset(value, 0, sizeof(value));
    }

    void Insert(char* word, int key)
    {
        int p = 0;
        for (int i = 0; word[i]; ++i)
        {
            int m = table[word[i]];
            if (!trie[p][m])
            {
                memset(trie[size], 0, sizeof(trie[0]));
                trie[p][m] = size++;
            }
            p = trie[p][m];
        }
        value[p] = key;
    }

    void Construct()
    {
        deque<int> que;

        for (int i = 0; i < CHILD_NUM; ++i)
            if (trie[0][i])
            {
                fail[trie[0][i]] = 0;
                que.push_back(trie[0][i]);
            }

        while (!que.empty())
        {
            int u = que.front();
            que.pop_front();

            for (int i = 0; i < CHILD_NUM; ++i)
            {
                int& v = trie[u][i];
                if (v)
                {
                    que.push_back(v);
                    fail[v] = trie[fail[u]][i];
                }
                else
                    v = trie[fail[u]][i];
            }
        }
    }

    int Work(char* word, int arr[])
    {
        memset(visit, false, sizeof(visit));

        int num = 0, p = 0;
        for (int i = 0; word[i]; ++i)
        {
            int m = table[word[i]];
            int t = p = trie[p][m];
            while (value[t] && !visit[t])
            {
                arr[num++] = value[t];
                visit[t] = true;
                t = fail[t];
                if (num >= 3)
                    return num;
            }
        }
        return num;
    }
};

AcAutomaton Ac;
char word[10010];

int main()
{
    int n;
    scanf("%d", &n);

    Ac.Initialize();
    Ac.Reset();

    char is[210];
    for (int i = 1; i <= n; ++i)
    {
        scanf("%s", is);
        Ac.Insert(is, i);
    }
    Ac.Construct();

    scanf("%d", &n);
    int count = 0;
    for (int i = 1; i <= n; ++i)
    {
        int arr[12], num = 0;

        scanf("%s", word);
        num = Ac.Work(word, arr);
        
        if (num)
        {
            sort(arr, arr + num);
            printf("web %d:", i);
            for (int j = 0; j < num; ++j)
                printf(" %d", arr[j]);
            printf("\n");
            ++count;
        }
    }
    printf("total: %d\n", count);
    return 0;
}