bzoj3224 Tyvj 1728 普通平衡树

#include<bits/stdc++.h>
#define N 1000000
using namespace std;
int n,opt,x;
int f[N+1],ch[N+1][2],key[N+1],cnt[N+1],siz[N+1],sz,rt;
inline char nc()
{
static char buf[100000],*p1=buf,*p2=buf;
return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline int read()
{
int x=0,f=1;
char c=nc();
while((c<'0'||c>'9')&&c!='-')c=nc();
if(c=='-')f=-1,c=nc();
while(c<='9'&&c>='0')x=x*10+c-'0',c=nc();
return x*f;
}
inline void clear(int x)
{
ch[x][0]=ch[x][1]=f[x]=key[x]=cnt[x]=siz[x]=0;
}
inline int get(int x)
{
return ch[f[x]][1]==x;
}
inline void update(int x)
{
if(!x)return;
siz[x]=cnt[x];
if(ch[x][0])siz[x]+=siz[ch[x][0]];
if(ch[x][1])siz[x]+=siz[ch[x][1]];
}
inline void rotate(int x)
{
int old=f[x],oldf=f[old],which=get(x);
ch[old][which]=ch[x][which^1];f[ch[old][which]]=old;
f[old]=x,ch[x][which^1]=old;
f[x]=oldf;
if(oldf)ch[oldf][ch[oldf][1]==old]=x;
update(old),update(x);
}
inline void splay(int x)
{
for(int fa;fa=f[x];rotate(x))
if(f[fa])rotate((get(x)==get(fa))?fa:x);
rt=x;
}
inline void insert(int x)
{
if(rt==0){sz++,clear(sz),key[sz]=x,cnt[sz]=1,siz[sz]=1,rt=sz;return;}
int now=rt,fa=0;
while(true)
{
if(key[now]==x)
{
cnt[now]++;
update(now),update(fa);
splay(now);
break;
}
fa=now;
now=ch[now][key[now]<x];
if(!now)
{
sz++;
clear(sz);
key[sz]=x,cnt[sz]=1,siz[sz]=1;
f[sz]=fa;ch[fa][key[fa]<x]=sz;
update(fa);
splay(sz);
break;
}
}
}
inline int find(int x)
{
int ans=0,now=rt;
while(true)
{
if(x<key[now])now=ch[now][0];
else
{
ans+=(ch[now][0]?siz[ch[now][0]]:0);
if(x==key[now]){splay(now);return ans+1;}
ans+=cnt[now];
now=ch[now][1];
}
}
}
inline int findx(int x)
{
int now=rt;
while(true)
{
if(ch[now][0]&&x<=siz[ch[now][0]])now=ch[now][0];
else
{
int tmp=(ch[now][0]?siz[ch[now][0]]:0)+cnt[now];
if(x<=tmp)return key[now];
x-=tmp,now=ch[now][1];
}
}
}
inline int pre()
{
int now=ch[rt][0];
while (ch[now][1]) now=ch[now][1];
return now;
}
inline int suf()
{
int now=ch[rt][1];
while (ch[now][0]) now=ch[now][0];
return now;
}
inline void del(int x)
{
int tmp=find(x);
if(cnt[rt]>1){cnt[rt]--;update(rt);return;}
if(!ch[rt][0]&&!ch[rt][1]){clear(rt);rt=0;return;}
if(!ch[rt][0])
{
int oldrt=rt;
rt=ch[rt][1];f[rt]=0;
clear(oldrt);
return;
}
if(!ch[rt][1])
{
int oldrt=rt;
rt=ch[rt][0];f[rt]=0;
clear(oldrt);
return;
}
int oldrt=rt,leftbig=pre();
splay(leftbig);
ch[rt][1]=ch[oldrt][1];
f[ch[oldrt][1]]=rt;
clear(oldrt);
update(rt);

}
int main()
{
//freopen("in.txt","r",stdin);
n=read();
for(int i=1;i<=n;i++)
{
opt=read(),x=read();
if(opt==1)insert(x);
if(opt==2)del(x);
if(opt==3)printf("%d\n",find(x));
if(opt==4)printf("%d\n",findx(x));
if(opt==5)insert(x),printf("%d\n",key[pre()]),del(x);
if(opt==6)insert(x),printf("%d\n",key[suf()]),del(x);
}
return 0;
}