解题：ZJOI 2006 书架

题面

学习了如何在维护序列的平衡树上查找某个数：按初始的顺序定个权值，然后每次找那个权值的DFS序即可。具体实现就是不停往上跳，然后是父亲的右儿子就加上父亲的左儿子，剩下的就是继续熟悉无旋树堆

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 using namespace std;
 const int N=;
 int num[N],val[N],siz[N],anc[N],son[N][],rnk[N];
 int n,m,w,x,y,z,rd,re,tot,pos,root; char ch[];
 void Pushup(int nde)
 {
     siz[nde]=siz[son[nde][]]+siz[son[nde][]]+;
     if(son[nde][]) anc[son[nde][]]=nde;
     if(son[nde][]) anc[son[nde][]]=nde;
 }
 int Create(int tsk)
 {
     siz[++tot]=;
     val[tot]=tsk;
     num[tsk]=tot;
     rnk[tot]=rand();
     return tot;
 }
 int Merge(int x,int y)
 {
     if(!x||!y) return x+y;
     else if(rnk[x]<=rnk[y])
     {
         son[x][]=Merge(son[x][],y);
         Pushup(x); return x;
     }
     else
     {
         son[y][]=Merge(x,son[y][]);
         Pushup(y); return y;
     }
 }
 void Split(int nde,int &x,int &y,int tsk)
 {
     if(!nde) x=y=;
     else
     {
         if(siz[son[nde][]]<tsk)
             x=nde,Split(son[nde][],son[nde][],y,tsk-siz[son[nde][]]-);
         else
             y=nde,Split(son[nde][],x,son[nde][],tsk);
         Pushup(nde);
     }
 }
 int Query(int nde)
 {
     int ret=siz[son[nde][]]+;
     while(anc[nde]) {
         if(nde==son[anc[nde]][])
         ret+=siz[son[anc[nde]][]]+;
         nde=anc[nde];
     }
     return ret;
 }
 void DFS(int nde)
 {
     if(son[nde][]) DFS(son[nde][]);
     printf("->%d",val[nde]);
     if(son[nde][]) DFS(son[nde][]);
 }
 int main()
 {
     srand();
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++)
         scanf("%d",&rd),root=Merge(root,Create(rd));
     while(m--)
     {
         scanf("%s%d",ch,&rd),pos=Query(num[rd]);
         if(ch[]=='T')
         {
             Split(root,x,z,pos),Split(x,x,y,pos-);
             root=Merge(Merge(y,x),z);
         }
         else if(ch[]=='B')
         {
             Split(root,x,z,pos),Split(x,x,y,pos-);
             root=Merge(Merge(x,z),y);
         }
         else if(ch[]=='I')
         {
             scanf("%d",&re);
             if(re==-)
             {
                 Split(root,w,z,pos),Split(w,w,y,pos-);
                 Split(w,w,x,pos-); root=Merge(Merge(Merge(w,y),x),z);
             }
             else if(re==)
             {
                 Split(root,y,z,pos+),Split(y,x,y,pos);
                 Split(x,w,x,pos-); root=Merge(Merge(Merge(w,y),x),z);
             }
         }
         else if(ch[]=='A')
             printf("%d\n",pos-);
         else
         {
             Split(root,x,z,rd),Split(x,x,y,rd-);
             printf("%d\n",val[y]);
             root=Merge(Merge(x,y),z);
         }
     }
     return ;
 }