参考于AgOH大佬的递归版splay做法！！！
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define re register
const int N=1e6+10;
void read(int &a)
{
a=0;int d=1;char ch;
while(ch=getchar(),ch>'9'||ch<'0')
if(ch=='-')
d=-1;
a=ch^48;
while(ch=getchar(),ch>='0'&&ch<='9')
a=(a<<3)+(a<<1)+(ch^48);
a*=d;
}
struct note{int l,r,siz,cnt,val;}spl[N];
int rt,cnt;
void newnode(int &now,int val)
{
spl[now=++cnt].val=val;
spl[now].siz=1;
spl[now].cnt=1;
}
void update(int now){spl[now].siz=spl[spl[now].l].siz+spl[spl[now].r].siz+spl[now].cnt;}
void zig(int &now)
{
int l=spl[now].l;
spl[now].l=spl[l].r;
spl[l].r=now;
now=l;
update(spl[now].r),update(now);
}
void zag(int &now)
{
int r=spl[now].r;
spl[now].r=spl[r].l;
spl[r].l=now;
now=r;
update(spl[now].l),update(now);
}
void splaying(int x,int &y)
{
if(x==y) return;
int &l=spl[y].l,&r=spl[y].r;
if(x==l) zig(y);
else if(x==r) zag(y);
else if(spl[x].val<spl[y].val)
{
if(spl[x].val<spl[l].val) splaying(x,spl[l].l),zig(y),zig(y);
else splaying(x,spl[l].r),zag(l),zig(y);
}
else
{
if(spl[x].val<spl[r].val) splaying(x,spl[r].l),zig(r),zag(y);
else splaying(x,spl[r].r),zag(y),zag(y);
}
}
void delnode(int now)
{
splaying(now,rt);
if(spl[now].cnt>1) spl[now].cnt--,spl[now].siz--;
else if(spl[now].r)
{
int p=spl[now].r;
while(spl[p].l) p=spl[p].l;
splaying(p,spl[now].r);
spl[spl[rt].r].l=spl[rt].l;
rt=spl[rt].r;
update(rt);
}
else rt=spl[now].l;
}
void ins(int &now,int val)
{
if(!now) newnode(now,val),splaying(now,rt);
else if(spl[now].val>val) ins(spl[now].l,val);
else if(spl[now].val<val) ins(spl[now].r,val);
else spl[now].cnt++,spl[now].siz++,splaying(now,rt);
}
void del(int &now,int val)
{
if(spl[now].val==val) delnode(now);
else if(spl[now].val>val) del(spl[now].l,val);
else del(spl[now].r,val);
}
int getnum(int rk)
{
int now=rt;
while(now)
{
int lsiz=spl[spl[now].l].siz;
if(lsiz+1<=rk&&rk<=lsiz+spl[now].cnt)
{
splaying(now,rt);
break;
}
else if(lsiz>=rk) now=spl[now].l;
else
{
rk-=lsiz+spl[now].cnt;
now=spl[now].r;
}
}
return spl[now].val;
}
int getrank(int val)
{
int now=rt,rk=1;
while(now)
{
if(spl[now].val==val)
{
rk+=spl[spl[now].l].siz;
splaying(now,rt);
break;
}
else if(spl[now].val>val) now=spl[now].l;
else
{
rk+=spl[now].cnt+spl[spl[now].l].siz;
now=spl[now].r;
}
}
return rk;
}
int main()
{
int n;read(n);
for(re int i=1,op,x;i<=n;i++)
{
read(op),read(x);
if(op==1) ins(rt,x);
else if(op==2) del(rt,x);
else if(op==3) printf("%d\n",getrank(x));
else if(op==4) printf("%d\n",getnum(x));
else if(op==5) printf("%d\n",getnum(getrank(x)-1));
else printf("%d\n",getnum(getrank(x+1)));
}
return 0;
}