uvalive5645 black box(普通treap)

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <cassert>
#include <stack>
using namespace std;
const int maxm=3000000+5;
struct {
    int v,r,siz;
    node* ch[2];
    void maintain()
    {
        int s=1;
        if(ch[0]!=NULL) s+=ch[0]->siz;
        if(ch[1]!=NULL) s+=ch[1]->siz;
        siz=s;
    }
    node(int x){
        this->v=x;
        this->r=rand();
        this->siz=1;
        this->ch[0]=this->ch[1]=NULL;
    }
    int cmp(int x)
    {
        if(x==v) return -1;
        else{
            return x<v?0:1;
        }
    }
};
node* rt;
void rotate(node* &o,int d)
{
    node* k=o->ch[d^1];
    o->ch[d^1]=k->ch[d];
    k->ch[d]=o;
    o->maintain();
    k->maintain();
    o=k;
}
void insert(node* &o,int x)
{
    if(o==NULL){
        o=new node(x);
        return;
    }
    else{
        int d=x<o->v?0:1;
        insert(o->ch[d],x);
        if(o->ch[d]->r > o->r) rotate(o,d^1);
        o->maintain();
    }
}
int kth(node* &o,int k)
{
    if(o==NULL || o->siz<k || k==0) return -1;
    int s=o->ch[0]==NULL?0:o->ch[0]->siz;
    if(k==s+1) return o->v;
    else if(k<=s) return kth(o->ch[0],k);
    else return kth(o->ch[1],k-s-1);
}
void print(node* &o)
{
    if(o==NULL) return;
    if(o->ch[0]!=NULL) print(o->ch[0]);
    printf("v=%d r=%d siz=%d || ",o->v,o->r,o->siz);
    if(o->ch[1]!=NULL) print(o->ch[1]);
}
int n,m;
int a[maxm],u[maxm];
stack<int > req;
int kas=0;
int main()
{
    scanf("%d",&kas);
    for(int z=0;z<kas;z++)
    {
        if(z>=1) puts("");
        memset(a,0,sizeof(a));
        memset(u,0,sizeof(u));
        rt=NULL;
        scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        for(int i=1;i<=m;i++) scanf("%d",&u[i]);
        for(int i=m;i>=1;i--) req.push(u[i]);
        int rnk=0;
        for(int i=1;i<=n;i++)
        {
            insert(rt,a[i]);
            while(req.size() && rt->siz==req.top()){
                req.pop();
                rnk++;
                printf("%dn",kth(rt,rnk));
            }
        }
    }
    return 0;
}