传送门

Description

1． Top S——表示把编号为S的书放在最上面。

2． Bottom S——表示把编号为S的书放在最下面。

3． Insert S T——T∈{-1，0，1}，若编号为S的书上面有X本书，则这条命令表示把这本书放回去后它的上面有X+T本书；

4． Ask S——询问编号为S的书的上面目前有多少本书。

5． Query S——询问从上面数起的第S本书的编号。

Solution

打算用它练习一下\(fhqTreap\)。

比较烦的是还要记下每个点的\(fa\)指针，才能计算它的排名

各种修改都是\(split\)然后\(merge\)一下就行了，简单

Code

#include<bits/stdc++.h>
#define ll long long
#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))
inline int read()
{int x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}return x*f;
}
#define MN 80005
class fhqTree
{private:int pri[MN],siz[MN],id[MN],fa[MN],ls[MN],rs[MN],val[MN],rt,sz;inline unsigned int random(){static unsigned int x=23333;return x^=x<<13,x^=x>>17,x^=x<<5;}inline int up(int x){if(ls[x])fa[ls[x]]=x;if(rs[x])fa[rs[x]]=x;return siz[x]=siz[ls[x]]+siz[rs[x]]+1;}inline void Split(int x,int k,int&rt1,int&rt2){if(!x) return(void)(rt1=rt2=0);if(siz[ls[x]]>=k) Split(ls[x],k,rt1,ls[x]),up(x),rt2=x;else Split(rs[x],k-siz[ls[x]]-1,rs[x],rt2),up(x),rt1=x;}inline int Merge(int rt1,int rt2){if(!(rt1*rt2)) return rt1|rt2;if(pri[rt1]<pri[rt2]) return rs[rt1]=Merge(rs[rt1],rt2),up(rt1),rt1;else return ls[rt2]=Merge(rt1,ls[rt2]),up(rt2),rt2;}inline void Build(int &x,int l,int r){if(l>r) return;x=++sz;pri[x]=random();if(l==r) return (void)(siz[x]=1,val[x]=read(),id[val[x]]=x);int mid=(l+r)>>1;Build(ls[x],l,mid-1);val[x]=read();id[val[x]]=x;Build(rs[x],mid+1,r);up(x);}inline int find(int x){#define get(x) (rs[fa[x]]==x)int res=siz[ls[x]]+1;for(;(x^rt)&&x;x=fa[x]) if(get(x)) res+=siz[ls[fa[x]]]+1;return res;}inline void Output(int x){if(!x) return;Output(ls[x]);printf("%d %d\n",val[x],val[fa[x]]);Output(rs[x]);}public:inline void build(int n){Build(rt,1,n);}inline void output(){Output(rt);puts("");}inline void Top(int x){register int k=find(id[x]),rt1,rt2,rt3,rt4;Split(rt,k,rt1,rt2);Split(rt1,k-1,rt3,rt4);rt=Merge(rt4,Merge(rt3,rt2));}inline void Bottom(int x){register int k=find(id[x]),rt1,rt2,rt3,rt4;Split(rt,k,rt1,rt2);Split(rt1,k-1,rt3,rt4);rt=Merge(rt3,Merge(rt2,rt4));}inline void Move(int x,int T){if(!T) return;register int k=find(id[x]),rt1,rt2,rt3,rt4,rt5,rt6;Split(rt,k,rt1,rt2);Split(rt1,k-1,rt3,rt4);if(T>0) Split(rt2,1,rt5,rt6),rt=Merge(rt3,Merge(rt5,Merge(rt4,rt6)));else  Split(rt3,k-2,rt5,rt6),rt=Merge(rt5,Merge(rt4,Merge(rt6,rt2)));}inline void Ask(int x){printf("%d\n",find(id[x])-1);}inline void Query(int k){register int rt1,rt2,rt3,rt4;Split(rt,k,rt1,rt2);Split(rt1,k-1,rt3,rt4);printf("%d\n",val[rt4]);rt=Merge(rt3,Merge(rt4,rt2));}
}T;
int main()
{register int x,n=read(),m=read(),i;T.build(n);register char s[20];while(m--){scanf("%s",s);x=read();if(s[0]=='T') T.Top(x);if(s[0]=='B') T.Bottom(x);if(s[0]=='I') T.Move(x,read());if(s[0]=='A') T.Ask(x);if(s[0]=='Q') T.Query(x);}return 0;
}

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