bzoj 3413: matching automaton + suffix tree merge segment

Not difficult ah, write the details thought out very relaxed -   

code: 

#include <bits/stdc++.h>    
#define N 200003     
#define LL long long  
#define setIO(s) freopen(s".in","r",stdin)  ,freopen(s".out","w",stdout)    
using namespace std;          
struct SAM 
{    
    int tot,last;    
    int ch[N<<1][10],pre[N<<1],len[N<<1];         
    void init() { last=tot=1;}     
    void extend(int c)  
    {
        int np=++tot,p=last;   
        len[np]=len[p]+1,last=np;   
        for(;p&&!ch[p][c];p=pre[p])  ch[p][c]=np;   
        if(!p) pre[np]=1; 
        else
        {        
            int q=ch[p][c];   
            if (as [q] as == [i] + 1) for the [NP] = q;  
            else 
            {
                int nq=++tot;  
                len[nq]=len[p]+1;   
                memcpy(ch[nq],ch[q],sizeof(ch[q]));  
                pre[nq]=pre[q],pre[q]=pre[np]=nq;  
                for(;p&&ch[p][c]==q;p=pre[p])    ch[p][c]=nq; 
            }
        }     
    }       
}s1,s2;           
int tot;   
char str[N]; 
int lson[N*30],rson[N*30],sum[N*30],rt[N<<1],tax[N<<1],rk[N<<1];     
int newnode() { return ++ tot; }    
void update(int &x,int l,int r,int p) 
{ 
    if(!x) x=newnode();  
    ++sum[x];  
    if(l==r) return ;  
    int mid=(l+r)>>1;     
    if(p<=mid)   update(lson[x],l,mid,p);  
    else    update(rson[x],mid+1,r,p);   
}    
int query(int x,int l,int r,int L,int R) 
{
    if(!x) return 0;  
    if(l>=L&&r<=R) { return sum[x]; }    
    int mid=(l+r)>>1, re=0; 
    if(L<=mid)     re+=query(lson[x],l,mid,L,R);   
    if(R>mid)      re+=query(rson[x],mid+1,r,L,R);   
    return re;   
}       
int merge(int x,int y) 
{ 
    if(!x||!y)   return x+y;  
    int now=newnode();   
    sum[now]=sum[x]+sum[y];      
    lson[now]=merge(lson[x],lson[y]);   
    rson[now]=merge(rson[x],rson[y]);   
    return now;      
}
int getmin(int x,int l,int r) 
{    
    if(l==r)     return l; 
    int mid=(l+r)>>1; 
    if(sum[lson[x]])    return getmin(lson[x],l,mid);   
    else return getmin(rson[x],mid+1,r);     
}
int main() 
{ 
    // setIO("input");           
    s1.init();  
    s2.init();            
    int n,i,j,m;      
    scanf("%d%s",&n,str+1);  
    for(i=1;i<=n;++i)   s1.extend(str[i]-'0'); 
    for(i=n;i>=1;--i) 
    { 
        s2.extend(str[i]-'0');                     
        int lst=s2.last;   
        update(rt[lst],1,n+1,i);                    
    // segment tree merger                
    }    
    for(i=1;i<=s2.tot;++i)   ++tax[s2.len[i]];  
    for(i=1;i<=s2.tot;++i)   tax[i]+=tax[i-1];  
    for(i=1;i<=s2.tot;++i)   rk[tax[s2.len[i]]--]=i;     
    for(i=s2.tot;i>1;--i)   
    {
        int u=rk[i];  
        int ff=s2.pre[u];   
        rt[ff]=merge(rt[ff],rt[u]);       
    }
    scanf("%d",&m);        
    for(i=1;i<=m;++i) 
    {     
        scanf("%s",str+1);    
        int length=strlen(str+1),pp=1,len=0,mn=n+1;  
        for(j=1;j<=length;++j) 
        {    
            if(s1.ch[pp][str[j]-'0'])  pp=s1.ch[pp][str[j]-'0'],++len;          
            else break;   
        }                                
        for(pp=1,j=len;j>=1;--j)  pp=s2.ch[pp][str[j]-'0'];                            
        if(len==length)    mn=getmin(rt[pp],1,n+1);                                 
        LL ans=0ll;         
        while(pp!=1)
        {         
            LL tmp=query(rt[pp],1,n+1,1,mn);                                                  
            ans+=tmp*(min(len,s2.len[pp])-s2.len[s2.pre[pp]]);                                
            pp=s2.pre[pp];       
        }               
        ans+=1ll*(mn-1ll); 
        printf("%lld\n",ans);    
    }             
    return 0;  
}