bzoj2002 彈飛綿羊

LCT 裸題，技巧是反着建邊才能維護向下路徑

/**************************************************************
    Problem: 2002
    User: Clare
    Language: C++
    Result: Accepted
    Time:1884 ms
    Memory:6036 kb
****************************************************************/
 
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <queue>
#include <vector>
#include <stack>
using namespace std;
 
#define N 200010
 
int n,m;
int size[N],fa[N],c[N][2],Next[N];
bool Rev[N];
stack<int> st;
 
inline int read()
{
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch<='9'&&ch>='0'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
 
void Pushup(int k)
{
    int l=c[k][0],r=c[k][1];
    size[k]=size[l]+size[r]+1;
}
 
void Pushdown(int k)
{
    int l=c[k][0],r=c[k][1];
    if(Rev[k])
    {
        Rev[k]^=1;Rev[r]^=1;Rev[l]^=1;
        swap(c[k][0],c[k][1]);
    }
}
 
bool Pd_root(int k)
{
    return !(c[fa[k]][0]==k)&&!(c[fa[k]][1]==k);
}
 
void Rotate(int x)
{
    int y=fa[x],z=fa[y],l,r;
    if(c[y][0]==x)l=0;else l=1;
    r=l^1;
    if(Pd_root(y));
    else if(c[z][0]==y)c[z][0]=x;
    else c[z][1]=x;
    fa[x]=z;fa[y]=x;fa[c[x][r]]=y;
    c[y][l]=c[x][r];c[x][r]=y;
    Pushup(y);Pushup(x);
}
 
void Splay(int x)
{
    st.push(x);
    for(int i=x;!Pd_root(i);i=fa[i])
    {
        st.push(fa[i]);
    }
    while(!st.empty())
    {
        int now=st.top();st.pop();
        Pushdown(now);
    }
    while(!Pd_root(x))
    {
        int y=fa[x],z=fa[y];
        if(!Pd_root(y))
        {
            if(c[y][0]==x^c[z][0]==y)
                Rotate(x);
            else Rotate(y);
        }
        Rotate(x);
    }
}
 
void Access(int x)
{
    for(int t=0;x;t=x,x=fa[x])
        Splay(x),c[x][1]=t,Pushup(x);
}
 
void Move_to_root(int x)
{
    Access(x);Splay(x);Rev[x]^=1;
}
 
void Join(int x,int y)
{
    Move_to_root(x);fa[x]=y;
}
 
void Cut(int x,int y)
{
    Move_to_root(x);Access(y);Splay(y);
    fa[x]=0;c[y][0]=0;
    Pushup(y);
}
 
void Split(int x,int y)
{
    Move_to_root(x);Access(y);Splay(y);
}
 
int main()
{
    n=read();
    for(int i=1;i<=n+1;i++)
        size[i]=1;
    for(int i=1;i<=n;i++)
    {
        int x=read();
        if(i+x>n)
            fa[i]=n+1,Next[i]=n+1;
        else fa[i]=i+x,Next[i]=i+x;
    }
    m=read();
    for(int i=1;i<=m;i++)
    {
        int kind=read();
        if(kind==1)
        {
            int x=read()+1;
            Move_to_root(n+1);Access(x);Splay(x);
            printf("%d\n",size[c[x][0]]);
        }
        else
        {
            int x=read()+1,y=read();
            if(x+y>n)
                y=n+1;
            else y=x+y;
            Cut(x,Next[x]);Join(x,y);
            Next[x]=y;
        }
    }
    return 0;
}