rt，请求大佬帮我调我的屎山代码

#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize(2)
//#pragma GCC optimize(3, "Ofast", "inline")
#define hh putchar('\n')
#define kg putchar(' ')
//#define int long long
//#define int __int128
namespace quickread{
	template<typename T> void read(T &x){
		x=0;char c=getchar();T neg=0;
		while(!isdigit(c)) neg|=!(c^'-'),c=getchar();
		while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
		if(neg) x=(~x)+1;
	}
	template<typename T> void write(T x){
		if(x<0) putchar('-'),x=~x+1;
		if(x>9) write(x/10);
		putchar(x%10^48);
	}
	inline string readstr(){
    	char ch=getchar();string str="";
		while(!(ch>='0'&&ch<='9')&&!(ch>='a'&&ch<='z')&&!(ch>='A'&&ch<='Z')) ch=getchar();
		while((ch>='0'&&ch<='9')||(ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z')){str+=ch;ch=getchar();}
		return str;
	}
	inline char readchar(){
		char ch=getchar();
		while(!(ch>='0'&&ch<='9')&&!(ch>='a'&&ch<='z')&&!(ch>='A'&&ch<='Z')) ch=getchar();
		return ch;
	}
}
using namespace quickread;
const int N=1e5+10,inf=2147483647;
mt19937 rnd(time(0));
int n,root=1;
namespace Treap{
	int cnt=0;
	struct node{
	    int ls,rs,fa;
	    int value,pri;
	    int cnt,siz;
	    node(){fa=ls=rs=0;value=pri=0;cnt=siz=0;}
	    void build(int val,int f){value=val;pri=rnd()%inf;cnt=siz=1;fa=f;}
	};
	node treap[N];
	void update(int p){treap[p].siz=treap[p].cnt+treap[treap[p].ls].siz+treap[treap[p].rs].siz;}
	void zig(int p){//右儿子上
	    int k=treap[p].rs;
	    if(p==1) root=k;
	    treap[p].rs=treap[k].ls,treap[treap[k].ls].fa=p;
	    treap[k].ls=p,treap[p].fa=k;
	    update(p),update(k);
	}
	void zag(int p){//左儿子上
	    int k=treap[p].ls;
	    if(p==1) root=k;
	    treap[p].ls=treap[k].rs,treap[treap[k].rs].fa=p;
	    treap[k].rs=p,treap[p].fa=k;
	    update(p),update(k);
	}
	void _insert(int p,int value){//opt==1
		if(!cnt) treap[++cnt].build(p,value);
		else if(value==treap[p].value) treap[p].cnt++;
		else if(value<treap[p].value){
			if(!treap[p].ls) _insert(treap[p].ls,value);
			else treap[++cnt].build(value,p),treap[p].ls=cnt;
			
			if(treap[treap[p].ls].pri<treap[p].pri) zag(p);
		}else{
			if(!treap[p].rs) _insert(treap[p].rs,value);
			else treap[++cnt].build(value,p),treap[p].rs=cnt;
			
			if(treap[treap[p].rs].pri<treap[p].pri) zig(p);
		}
		update(p);
	} 
	void _delete(int p,int value){//opt==2
		if(value>treap[p].value) _delete(treap[p].rs,value);
		else if(value<treap[p].value) _delete(treap[p].ls,value);
		else {
			if(treap[p].cnt>1) treap[p].cnt--;
			else {
				if(!treap[p].ls&&!treap[p].rs){
					int k=treap[p].fa;
					if(treap[k].ls==p) treap[k].ls=0;
					else treap[k].rs=0;
					treap[p].fa=treap[p].ls=treap[p].rs=0;
					treap[p].value=treap[p].pri=0;
					treap[p].cnt=treap[p].siz=0;
				}else if(!treap[p].ls&&treap[p].rs){
					int k=treap[p].fa;
					if(treap[k].ls==p) treap[k].ls=treap[p].rs;
					else treap[k].rs=treap[p].rs;
					treap[treap[p].rs].fa=k;
					treap[p].fa=treap[p].ls=treap[p].rs=0;
					treap[p].value=treap[p].pri=0;
					treap[p].cnt=treap[p].siz=0;
				}else if(treap[p].ls&&!treap[p].rs){
					int k=treap[p].fa;
					if(treap[k].ls==p) treap[k].ls=treap[p].ls;
					else treap[k].rs=treap[p].ls;
					treap[treap[p].ls].fa=k;
					treap[p].fa=treap[p].ls=treap[p].rs=0;
					treap[p].value=treap[p].pri=0;
					treap[p].cnt=treap[p].siz=0;
				}else{
					int k=0;
					if(treap[treap[p].ls].pri>treap[treap[p].rs].pri) k=1;
					if(!k) zag(p),_delete(p,value);else zig(p),_delete(p,value);
				}
			}
		}
		update(p);
	}
	int ans=0;
	int query_kth1(int p,int x){//opt==4
		int ans1=1;
		if(p==0) ans1=0;
		else if(x<treap[p].value) ans1=query_kth1(treap[p].ls,x);
		else if(x==treap[p].value) ans1=treap[treap[p].ls].siz+1;
		else ans1=query_kth1(treap[p].rs,x)+1+treap[treap[p].ls].siz;
		return ans1;
	}
	int query_kth2(int p,int x){//opt==3
		int ans1=0;
		if(p==0) ans1=0;
		else if(x==treap[treap[p].ls].siz+1) ans1=treap[p].value;
		else if(x>treap[treap[p].ls].siz+1) ans1=query_kth2(treap[p].rs,x-treap[treap[p].ls].siz-1);
		else ans1=query_kth2(treap[p].ls,x);
		return ans1;
	}
	void query_pre(int p,int x){//opt==5
		if(p==0) return;
		if(x>treap[p].value){
			ans=max(ans,treap[p].value);
			query_pre(treap[p].rs,x);
		}else query_pre(treap[p].ls,x);
		return;
	}
	void query_nex(int p,int x){//opt==6
		if(p==0) return;
		if(x<treap[p].value){
			ans=min(ans,treap[p].value);
			query_nex(treap[p].ls,x);
		}else query_nex(treap[p].rs,x);
		return;
	}

	void debug(int p){
		cout<<"treap["<<p<<"].value="<<treap[p].value<< " ";
		cout<<"treap["<<p<<"].size="<<treap[p].siz<<" ";
		cout<<"treap["<<p<<"].ls="<<treap[p].ls<<" ";
		cout<<"treap["<<p<<"].rs="<<treap[p].rs<<" ";

		cout<<"\n";
		if(treap[p].ls!=-1) debug(treap[p].ls);
		if(treap[p].rs!=-1) debug(treap[p].rs);
	}
}
using namespace Treap;
signed main(){
//	ios::sync_with_stdio(0);
//	cin.tie(0);cout.tie(0);
	read(n);
	for(int i=1;i<=n;i++){
		int opt,x;read(opt),read(x);
		if(opt==1) _insert(root,x);
		else if(opt==2) _delete(root,x);
		else if(opt==3) write(query_kth2(root,x)),hh;
		else if(opt==4) write(query_kth1(root,x)),hh;
		else if(opt==5) ans=-inf,query_pre(root,x),write(ans),hh;
		else ans=inf,query_nex(root,x),write(ans),hh;
	}
	return 0;
}