bzoj 2434: [Noi2011]阿狸的打字机

/**************************************************************
    Problem: 2434
    User: wangyucheng
    Language: C++
    Result: Accepted
    Time:496 ms
    Memory:21968 kb
****************************************************************/
 
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define in(x) scanf("%d",&x)
#define in2(x,y) scanf("%d%d",&x,&y)
#define in3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define F(i,x) for(int i=1;i<=x;i++)
#define N 110000
int p[N][30];
int g[N],nn;
char a[N];
int to[N];
int im[N],n,fa[N],tot,m;
int s[N*2];
void make(){
    int now=0;
    for(int i=0;i<n;i++){
        if(a[i]==‘B‘){
            now=fa[now];
            continue;
        }
        if(a[i]==‘P‘){
          im[now]=++nn;
          to[nn]=now;
          continue; 
        }
        if(!p[now][a[i]-‘a‘])p[now][a[i]-‘a‘]=++tot,fa[tot]=now;
        now=p[now][a[i]-‘a‘];       
    }
}
int tt,e[N],ne[N],v[N];
int tt2,e2[N],ne2[N],v2[N],num[N];
void add(int x,int y){
    ne[++tt]=e[x],e[x]=tt,v[tt]=y;
}
void add2(int x,int y,int z){
    ne2[++tt2]=e2[x],e2[x]=tt2,num[tt2]=z,v2[tt2]=y;
}
int qu[N],he,bo;
void bfs(){
    int y,x;
    qu[he=bo=1]=0;
    while(he>=bo){
        x=qu[bo++];
        for(int i=0;i<26;i++)if(p[x][i]){
            qu[++he]=p[x][i];
            int z=g[x];
            for(;z!=-1&&!p[z][i];z=g[z]);
            if(z==-1)g[qu[he]]=0;
            else g[qu[he]]=p[z][i];
        }
    }
}
int b1[N],b2[N],len;
void jia(int x,int y){
    for(int i=x;i<=len;i+=(i&-i))s[i]+=y;    
}
int ask(int x){
    int ans=0;
    for(int i=x;i>0;i-=(i&-i))ans+=s[i];
    return ans;
}
void dfs1(int x){
     b1[x]=++len;
     for(int i=e[x];i;i=ne[i]){
        dfs1(v[i]);
     }
     b2[x]=len;
}
int res[N];
void solv(){
    int now=0,k;
    for(int i=0;i<n;i++){
        if(a[i]==‘B‘){
            jia(b1[now],-1);
            now=fa[now];
            continue;
        }
        if(a[i]==‘P‘){
          for(int j=e2[im[now]];j;j=ne2[j]){
            k=to[v2[j]];
            res[num[j]]=ask(b2[k])-ask(b1[k]-1);
          }
          continue; 
        }   
        now=p[now][a[i]-‘a‘];
        jia(b1[now],1);
    }
}
int main(){
    scanf("%s",a);
    g[0]=-1;
    n=strlen(a);
    in(m);
    make();
    bfs();
    F(i,tot)add(g[i],i);
    F(i,m){
        int x,y;
        in2(x,y);
        add2(y,x,i);
    }
    dfs1(0);
    solv();
    F(i,m)printf("%d\n",res[i]);
}