HDU 5056 Harry And Biological Teacher

struct SAM
{
    SAM *son[4],*pre;
    int len;
	int ok;

	void init()
	{
		clr(son,0);
		pre=0;
		ok=0;
	}
};


SAM sam[N],*head,*last;
int cnt;


void initSam()
{
    head=last=&sam[0];
	head->init();
    cnt=1;
}


int get(char x)
{
	if(x==‘A‘) return 0;
	if(x==‘T‘) return 1;
	if(x==‘G‘) return 2;
	return 3;
}

void insert(int x)
{
    SAM *p=&sam[cnt++],*u=last;

	p->init();

    p->len=last->len+1;
    last=p;
    for(;u&&!u->son[x];u=u->pre) u->son[x]=p;
    if(!u) p->pre=head;
    else if(u->son[x]->len==u->len+1) p->pre=u->son[x];
    else
    {
        SAM *r=&sam[cnt++],*q=u->son[x];
        *r=*q; r->len=u->len+1;
        p->pre=q->pre=r;
        for(;u&&u->son[x]==q;u=u->pre) u->son[x]=r;
    }
}


char s[N*2];
int cur;

int start[N],len[N];

vector<pair<int,int> > V[N];

int ans[N];


map<int,int> mp;


int n,m;

int main()
{
//	FFF;

	while(scanf("%d%d",&n,&m)!=-1)
	{
		cur=0;
		int i;
		for(i=1;i<=n;i++)
		{
			scanf("%s",s+cur);
			start[i]=cur;
			len[i]=strlen(s+cur);
			cur+=len[i]+3;
		}
		for(i=1;i<=m;i++)
		{
			int u,v;
			scanf("%d%d",&u,&v);
			V[u].pb(MP(v,i));
		}

		
		for(i=1;i<=n;i++) if(SZ(V[i])>0)
		{
			int j;
			initSam();
			for(j=start[i];s[j];j++)  insert(get(s[j]));
			SAM *p=last;
			while(p!=NULL) p->ok=1,p=p->pre;


			mp.clear();
			for(j=0;j<SZ(V[i]);j++)
			{
				int k=V[i][j].first;
				int id=V[i][j].second;
				if(mp.count(k))
				{
					ans[id]=mp[k];
					continue;
				}
				SAM *p=head;
				int t,tmp=0,cur=0;
				for(t=start[k];s[t];t++)
				{
					int x=get(s[t]);
					if(p->son[x])
					{
						cur++;
						p=p->son[x];
						if(p->ok) tmp=max(tmp,cur);
					}
					else break;
				}
				mp[k]=tmp;
				ans[id]=tmp;
			}
			V[i].clear();
		}
		for(i=1;i<=m;i++) printf("%d\n",ans[i]);
	}
}