splay模板

#include"bits/stdc++.h"
using namespace std;


int n,m;
int root=0; int tot;
const int nn = 200000;
int cnt[nn]; int v[nn];
int ch[nn][2]; int fa[nn];
int size[nn];

inline void push(int x)
{
    size[x]=size[ch[x][0]]+size[ch[x][1]]+cnt[x];
    return ;
}
inline void rot(int x,int d)
{
    int y=fa[x]; int z=fa[y];
    ch[y][d^1]=ch[x][d];
    fa[ch[x][d]]=y;
    ch[x][d]=y;
    fa[y]=x;
    push(y),push(x);
    int t = ch[z][1]==y;
    if (z)ch[z][t]=x;
    fa[x]=z;
    if (z)push(z);
    return ;
    
}


inline void splay(int x,int goal=0)
{
    while (fa[x]!=goal)
    {
        int y=fa[x]; int z=fa[y];
        if (z==goal)
        {
            rot(x,(ch[y][1]==x)^1); break;  // 有个^
            
        }
        else 
        {
            if (ch[z][1]==y) 
            if (ch[y][1]==x)rot(y,0),rot(x,0);
            else rot(x,1),rot(x,0);
            else if (ch[y][0]==x)rot(y,1),rot(x,1);
            else rot(x,0),rot(x,1); 
        }
    }
    if (!goal)root=x;
}

inline void insert(int x)
{
    int now = root;
    while (1)
    {
        if (v[now]==x)
        {
        cnt[now]++,splay(now);push(now);tot++;
        break;
        }
        if (!ch[now][x>v[now]])
        {ch[now][x>v[now]]=++tot,cnt[tot]=1,size[tot]=1,v[tot]=x;    
        fa[tot]=now;splay(tot);
    break;}
        now=ch[now][x>v[now]];        
    }
}

int find(int x)
{   int now =root;
    while (1)
    {
        if (x<=size[ch[now][0]])now=ch[now][0];
        else if (x>size[ch[now][0]]+cnt[now])x-=size[ch[now][0]]+cnt[now],
                                             now=ch[now][1];
       else return now;
    }
}

void print(int x)
{
    if (!x)return ;
    int l=ch[x][0],r=ch[x][1];
    cout<<l<<" "<<r<<" "<<v[l]<<" "<<v[r]<<" "<<fa[x]<<" "<<v[x]<<" "<<size[x]<<endl;
    print(l);
    print(r); 
}

int main()
{
    cin>>n;
    
    for (int i=1;i<=n;i++)
    {
        int x;scanf("%d",&x);
        if (!root)root=++tot,cnt[tot]=1,size[tot]=1,v[tot]=x;
        else insert(x);
        

    }cin>>m;
    while (m--)
    {
        char s[10];
        cin>>s;
        if (s[0]=='a')
        {
            int x;scanf("%d",&x);insert(x);
            
        }else printf("%d
",v[find(tot/2+(tot&1))]);
    }
    
}