fhq_treap || BZOJ 3224: Tyvj 1728 普通平衡树 || Luogu P3369 【模板】普通平衡树

题面：【模板】普通平衡树

代码：

 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #include<cstdlib>
 using namespace std;
 inline int rd(){
     int x=,f=;char c=getchar();
     while(c<''||c>''){if(c=='-')f=-; c=getchar();}
     while(c>=''&&c<=''){x=x*+c-''; c=getchar();}
     return f*x;
 }
 const int maxn=(2e5)+;
 int N,chd[maxn][],a,o,val[maxn],rt,x,y,z,g,pr[maxn],tot=,siz[maxn];
 inline int New_node(int a){
     val[++tot]=a;
     pr[tot]=rand();
     siz[tot]=;
     return tot;
 }
 inline void Pushup(int a){
     siz[a]=siz[chd[a][]]+siz[chd[a][]]+;
     return;
 }
 inline void Split(int now,int k,int &x,int &y){
     if(!now){x=y=; return;}
     if(val[now]<=k){
         x=now;
         Split(chd[now][],k,chd[now][],y);
     }
     else{
         y=now;
         Split(chd[now][],k,x,chd[now][]);
     }
     Pushup(now);
     return;
 }
 inline int Merge(int a,int b){
     if(!a||!b)return (a+b);
     if(pr[a]<pr[b]){
         chd[a][]=Merge(chd[a][],b);
         Pushup(a);
         return a;
     }
     else{
         chd[b][]=Merge(a,chd[b][]);
         Pushup(b);
         return b;
     }
 }
 inline int Kth(int now,int k){
     while(now){
         if(k<=siz[chd[now][]])now=chd[now][];
         else if(k==siz[chd[now][]]+)return now;
         else k=k-siz[chd[now][]]-,now=chd[now][];
     }
     return now;
 }
 int main(){
     srand();
     N=rd();
     rt=;
     while(N--){
         o=rd();a=rd();
         if(o==){
             Split(rt,a,x,y);
             rt=Merge(Merge(x,New_node(a)),y);
         }
         else if(o==){
             Split(rt,a,x,z);
             Split(x,a-,x,y);
             rt=Merge(Merge(x,Merge(chd[y][],chd[y][])),z);
         }
         else if(o==){
             Split(rt,a-,x,y);
             printf("%d\n",siz[x]+);
             rt=Merge(x,y);
         }
         else if(o==){
             printf("%d\n",val[Kth(rt,a)]);
         }
         else if(o==){
             Split(rt,a-,x,y);
             printf("%d\n",val[Kth(x,siz[x])]);
             rt=Merge(x,y);
         }
         else{//o==6
             Split(rt,a,x,y);
             printf("%d\n",val[Kth(y,)]);
             rt=Merge(x,y);
         }
     }
     return ;
 }

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By:AlenaNuna