标签：

Computer Virus on Planet Pandora

3
2
AB
DCB
DACB
3
ABC
CDE
GHI
ABCCDEFIHG
4
ABB
ACDEE
BBB
FEEE
A[2B]CD[4E]F

0
3
2
Hint
In the second case in the sample input, the reverse of the program is ‘GHIFEDCCBA’, and ‘GHI’ is a substring of the reverse, so the program is infected 
by virus ‘GHI’.
 

裸题瞬秒
ac代码

#include<stdio.h>
#include<string.h>
char str[5100000],key[1010],ss[5100000];
int head,tail;
struct node
{
    node *fail;
    node *next[26];
    int cnt;
    node()
    {
        fail=NULL;
        cnt=0;
        for(int i=0;i<26;i++)
            next[i]=NULL;
    }
}*q[252000];
node *root;
void insert(char *s)
{
    int temp,len,i;
    node *p=root;
    len=strlen(s);
    for(i=0;i<len;i++)
    {
        temp=s[i]-'A';
        if(p->next[temp]==NULL)
            p->next[temp]=new node();
        p=p->next[temp];
    }
    p->cnt++;
}
void build_ac()
{
    root->fail=NULL;
    q[tail++]=root;
    while(head!=tail)
    {
        node *p=q[head++];
        node *temp=NULL;
        for(int i=0;i<26;i++)
        {
            if(p->next[i]!=NULL)
            {
                if(p==root)
                {
                    p->next[i]->fail=root;
                }
                else
                {
                    temp=p->fail;
                    while(temp!=NULL)
                    {
                        if(temp->next[i]!=NULL)
                        {
                            p->next[i]->fail=temp->next[i];
                            break;
                        }
                        temp=temp->fail;
                    }
                    if(temp==NULL)
                    {
                        p->next[i]->fail=root;
                    }
                }
                q[tail++]=p->next[i];
            }
        }
    }
}
int query()
{
    int ans=0;
    int len=strlen(str);
    node *p=root,*temp;
    for(int i=0;i<len;i++)
    {
        int x=str[i]-'A';
        while(p->next[x]==NULL&&p!=root)
        {
            p=p->fail;
        }
        p=p->next[x];
        if(p==NULL)
        {
            p=root;
        }
        temp=p;
        while(temp!=root&&temp->cnt!=-1)
        {
            ans+=temp->cnt;
            temp->cnt=-1;
            temp=temp->fail;
        }
    }
    return ans;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n;
        scanf("%d",&n);
        int i;
        head=tail=0;
        root=new node();
        for(i=0;i<n;i++)
        {
            scanf("%s",key);
            insert(key);
        }
        build_ac();
        scanf("%s",ss);
        int len=strlen(ss),j=0,k1;
        for(i=0;i<len;)
        {
            if(ss[i]=='[')
            {
                i++;
                int num=0;
                while(ss[i]>='0'&&ss[i]<='9')
                {
                    num=num*10+(ss[i]-'0');
                    i++;
                }
                while(num--)
                {
                    str[j++]=ss[i];
                }
                i+=2;
            }
            else
                str[j++]=ss[i++];
        }
		str[j]='\0';
    //    printf("%s\n",str);
		int ans=query();
		len=strlen(str);
		for(i=0;i<=(len-1)/2;i++)
		{
			char ch=str[len-1-i];
			str[len-1-i]=str[i];
			str[i]=ch;
		}
		ans+=query();
        printf("%d\n",ans);
    }
}

HDOJ 题目3695 Computer Virus on Planet Pandora（AC自动机）

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原文地址：http://blog.csdn.net/yu_ch_sh/article/details/47335669