[HDU2896]病毒侵袭[AC自动机]

题意:

多模式串匹配,输出模式串的ID

思路:

典型AC自动机.

用向量存储答案ID

#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
const int MAXL = 130;
/*
inline int GetID(char x)
{
    return x;
}*/
class node{
public:
    node* chd[MAXL];
    node* fail;
    int cnt;

    node(){
        fail = NULL;
        memset(chd,0,sizeof(chd));
        cnt = 0;
    }
};

vector  ans;

class AC_Automation{
public:
    node* root;
    queue q;

    AC_Automation(){
        root = new node;
        while(!q.empty())   q.pop();
    }

    void insert(string s,int x)
    {
        node* cur = root;
        for(int i=0;i        {
            int index = s[i];
            if(cur->chd[index] == NULL)    cur->chd[index] = new node;
            cur = cur->chd[index];
        }
        cur->cnt = x;
    }

    void BuildAC()
    {
        node *cur,*tmp;
        q.push(root);
        while(!q.empty())
        {
            cur = q.front();
            q.pop();
            for(int i = 0; i             {
                if(cur->chd[i])
                {//只有root->fail = NULL;
                    if(cur==root)   cur->chd[i]->fail = root;
                    else
                    {
                        tmp = cur->fail;
                        while(tmp->fail && !tmp->chd[i])    tmp = tmp->fail;
                        if(tmp->chd[i])     cur->chd[i]->fail = tmp->chd[i];
                        else    cur->chd[i]->fail = root;
                    }
                    q.push(cur->chd[i]);
                }
            }
        }
    }

    void query(string s)
    {//用指针时,指向根节点和指向空要分别对待;在fail的构造中已经解决了指向根的跳回
        //只需要注意指向空的时候跳回指向根
        node *cur = root, *tmp;
        for(int i=0;i        {
            int index = s[i];
            if(cur->chd[index]) cur = cur->chd[index];
            else
            {
                while(cur && !cur->chd[index])  cur = cur->fail;
                if(!cur)    cur = root;
                if(cur->chd[index])     cur = cur->chd[index];
            }
            tmp = cur;
            while(tmp->fail && tmp->cnt)
            {
                ans.push_back(tmp->cnt);
                if(ans.size()==3)   return;
                tmp = tmp->fail;
            }
        }
    }
};
char pat[205],tar[10005];

int main()
{
    int n;
    while(scanf("%d",&n)==1)
    {
        AC_Automation AC;
        for(int i=1; i<=n; i++)
        {
            getchar();
            gets(pat);
            AC.insert(pat,i);
        }
        AC.BuildAC();
        int m,tot = 0;
        scanf("%d",&m);
        for(int i=1;i<=m;i++)
        {
            getchar();
            gets(tar);
            ans.clear();
            AC.query(tar);
            if(ans.size())
            {
                sort(ans.begin(),ans.end());
                printf("web %d:",i);
                for(int j=0;j                puts("");
                tot++;
            }
        }
        printf("total: %d\n",tot);
    }
}