題意：輸入m個數，詢問n個數，第一個數如果是3，就輸出在m的第三個數輸入完成後第1大的數，第二個就輸出第二大的數，但前提都是在輸入完U[i]個數後

思路：用平衡樹Treap進行插入和查詢第K大的數，模版題

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
const int inf=0x3f3f3f3f;
const int maxn=100010;
class Treap{
    public:
struct Treap_Node{
    Treap_Node *left,*right;
    int value,fix,weight,size;//fix為修正值，是隨機產生的，保證二叉樹不會退化的重要環節，wweight為權值，size為子樹大小
}*root,*null;
Treap(){
    null=new struct Treap_Node;
    null->size=0;
    null->weight=0;
    null->value=inf;
    null->left=null;
    null->right=null;
    null->fix=inf;
    root=null;
}
void Treap_Print(Treap_Node *P){//從小到大輸出
    if(P!=null){
        Treap_Print(P->left);
        printf("%d\n",P->value);
        Treap_Print(P->right);
    }
}
void Treap_Left_Rotate(Treap_Node *&a){//左旋之後仍不改變二叉樹性質
    Treap_Node *b=a->right;
    a->right=b->left;
    b->left=a;
    b->size=a->size;
    a->size=a->left->size+a->right->size+a->weight;
    a=b;
}
void Treap_Right_Rotate(Treap_Node *&a){//右旋之後仍不改變二叉樹性質
    Treap_Node *b=a->left;
    a->left=b->right;
    b->right=a;
    b->size=a->size;
    a->size=a->left->size+a->right->size+a->weight;
    a=b;
}
int Treap_Find(Treap_Node *P,int value){//查詢有沒有value這個數
    if(P==null) return 0;
    if(P->value==value) return 1;
    else if(value<P->value) return Treap_Find(P->left,value);
    else return Treap_Find(P->right,value);
}
void Treap_Insert(Treap_Node *&P,int value){//插入一個數
    if(P==null){
        P=new Treap_Node;
        P->left=P->right=null;//左右兒子均為空
        P->value=value;
        P->fix=rand();
        P->weight=1;
        P->size=1;
    }else if(value==P->value){
        P->weight++;
    }
    else if(value<P->value){
        Treap_Insert(P->left,value);
        if(P->left->fix<P->fix)
            Treap_Right_Rotate(P);
    }else{
        Treap_Insert(P->right,value);
        if(P->right->fix<P->fix)
            Treap_Left_Rotate(P);
    }
    P->size=P->left->size+P->right->size+P->weight;
}
void Treap_Delete(Treap_Node *&P,int value){//刪除一個數
    if(P==null) return ;
    if(value<P->value) Treap_Delete(P->left,value);
    else if(value>P->value) Treap_Delete(P->right,value);
    else if(P->weight>1) P->weight--;
    else if((P->left==NULL)&&(P->right==NULL)){
        delete P;
        P=NULL;
    }else{
        if(P->left->fix<P->right->fix) Treap_Left_Rotate(P);
        else Treap_Right_Rotate(P);
        Treap_Delete(P,value);
    }
    P->size=P->left->size+P->right->size+P->weight;
}
int Treap_pred(Treap_Node *P,int value,Treap_Node *optimal){//前驅
    if(P==null||value==P->value) return optimal->value;
    if(P->value<value) return Treap_pred(P->right,value,P);
    else return Treap_pred(P->left,value,optimal);
}
int Treap_succ(Treap_Node *P,int value,Treap_Node *optimal){//後繼
    if(P==null||value==P->value) return optimal->value;
    if(P->value>value) return Treap_succ(P->left,value,P);
    else return Treap_succ(P->right,value,optimal);
}
int Treap_Findkth(Treap_Node *P,int k){//求第K大的數
    if(P==null) return 0;
    int t=P->left->size;
    if(k<t+1) return Treap_Findkth(P->left,k);
    else if(k>t+P->weight) return Treap_Findkth(P->right,k-(t+P->weight));
    else return P->value;
}
int Treap_Rank(Treap_Node *P,int value,int cur){//求這個數的排名
    int t=P->left->size;
    if(value==P->value) return t+cur+1;
    else if(value<P->value) return Treap_Rank(P->left,value,cur);
    else return Treap_Rank(P->right,value,t+cur+P->weight);
}
void Treap_erase(Treap_Node *&P) {//將樹清空
		if(P->left!=null)
			Treap_erase(P->left);
		if(P->right!=null)
			Treap_erase(P->right);
		delete P;
}
};
int num[30010],num1[50010];
int main(){
    int n,a,b,m;
    while(scanf("%d%d",&n,&m)!=-1){
        Treap tree;
        for(int i=1;i<=n;i++) scanf("%d",&num[i]);
        int t=1,k=1;
        for(int i=1;i<=m;i++) scanf("%d",&num1[i]);
        while(t<=m){
            while(k<=num1[t]){
                tree.Treap_Insert(tree.root,num[k]);
                k++;
            }
            int ans=tree.Treap_Findkth(tree.root,t++);
            printf("%d\n",ans);
        }
    }
    return 0;
}
 

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int inf=0x3f3f3f3f;
const ll INF=0x3f3f3f3f3f3f3f3fll;
const int maxn=15010;
struct Node{
    Node *ch[2];
    int r,v,s;
    Node(int v):v(v){ch[0]=ch[1]=NULL;r=rand();s=1;}
    int cmp(int x){
        if(x==v) return -1;
        return x<v? 0:1;
    }
    void maintain(){
        s=1;
        if(ch[0]!=NULL) s+=ch[0]->s;
        if(ch[1]!=NULL) s+=ch[1]->s;
    }
};
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);
    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();
}
void Remove(Node* &o,int x){
    int d=o->cmp(x);
    if(d==-1){
        Node* u=o;
        if(o->ch[0]!=NULL&&o->ch[1]!=NULL){
            int d2=(o->ch[0]->r>o->ch[1]->r?1:0);
            Rotate(o,d2);Remove(o->ch[d2],x);
        }else{
            if(o->ch[0]==NULL) o=o->ch[1];
            else o=o->ch[0];
            delete u;
        }
    }else Remove(o->ch[d],x);
    if(o!=NULL) o->maintain();
}
int Kth(Node* &o,int k){//第K大的值
    if(o==NULL||k<=0||k>o->s) return 0;
    int s=(o->ch[0]==NULL?0:o->ch[0]->s);
    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);
}
int Rank(Node* &o,int x){//x的排名
    if(o==NULL) return -1;//未找到
    int num=o->ch[0]==NULL?0:o->ch[0]->s;
    if(x==o->v) return num+1;
    else if(x<o->v) return Rank(o->ch[0],x);
    else return Rank(o->ch[1],x)+num+1;
}
void deletetree(Node* &o){
    if(o->ch[0]!=NULL) deletetree(o->ch[0]);
    if(o->ch[1]!=NULL) deletetree(o->ch[1]);
    delete o;o=NULL;
}
int num[30010],num1[50010];
int main(){
    int n,m,a,b;
    while(scanf("%d%d",&n,&m)!=-1){
        Node* root=NULL;
        for(int i=1;i<=n;i++) scanf("%d",&num[i]);
        for(int i=1;i<=m;i++) scanf("%d",&num1[i]);
        int t=1,k=1;
        while(t<=m){
            while(k<=num1[t]){
                Insert(root,num[k]);
                k++;
            }
            int ans=Kth(root,t++);
            printf("%d\n",ans);
        }
        deletetree(root);
    }
    return 0;
}