#include<iostream>
#include<cstdlib>
#include<ctime>
using namespace std;
int root=1,ftsize=0;
struct ftreap
{
    int ls,rs,size,v,w;
} ft[100005];
void update(int t)
{
    ft[t].size=ft[ft[t].ls].size+ft[ft[t].rs].size+1;
}
int newdata(int x)
{
    int id=++ftsize;
    ft[id].size=1;
    ft[id].v=x;
    ft[id].w=rand();
    return id;
}
void split(int t,int val,int &x,int &y)
{
    if(!t) 
    {
        x=y=0;
        return;
    }
    if (ft[t].v<=val)
    {
        x=t;
        split(ft[t].rs,val,ft[t].rs,y);
    } 
    else
    {
        y=t;
        split(ft[t].ls,val,x,ft[t].ls);
    }
    update(t);
}
int merge(int x,int y)
{
    if(!x||!y) return x+y;
    if(ft[x].w<ft[y].w)
    {
        ft[y].ls=merge(x,ft[y].ls);
        update(y);
        return y;
    } else
    {
        ft[x].rs=merge(ft[x].rs,y);
        update(x);
        return x;
    }
}
void insert(int x)
{
    int i,j;
    split(root,x,i,j);
    root=merge(i,merge(newdata(x),j));
}
void del(int x)
{
    int i,j,k,l,m;
    split(root,x,i,j);
    split(i,x-1,k,l);
    m=merge(ft[l].ls,ft[l].rs);
    root=merge(merge(k,m),j);
}
int get_rank(int x)
{
    int i,j,res;
    split(root,x-1,i,j);
    res=ft[i].size+1;
    root=merge(i,j);
    return res;
}
int kth(int t,int k)
{
    if(k==ft[ft[t].ls].size+1) return t;
    if(k<=ft[ft[t].ls].size) return kth(ft[t].ls,t);
    else return kth(ft[t].rs,t-ft[ft[t].ls].size-1);
}
int pre(int x)
{
    int i,j;
    split(root,x-1,i,j);
    int res=ft[kth(i,ft[i].size)].v;
    root=merge(i,j);
    return res;
}
int next(int x)
{
    int i,j;
    split(root,x,i,j);
    int res=ft[kth(j,1)].v;
    root=merge(i,j);
    return res;
}
int main()
{
    srand(time(NULL));
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        int opt,x;
        cin>>opt>>x;
        switch (opt)
        {
            case 1:
                insert(x);
                break;
            case 2:
                del(x);
                break;
            case 3:
                cout<<get_rank(x)<<endl;
                break;
            case 4: 
                cout<<ft[kth(root,x)].v<<endl;
                break;
            case 5:
                cout<<pre(x)<<endl;
                break;
            case 6:
                cout<<next(x)<<endl;
                break;
        }
    }
    return 0;
} 

为什么会MLE