upd：44pts
```cpp
#include <bits/stdc++.h>
namespace tree {
class AVL_tree {
private:
struct node {
int key, count, size, height;
node *left, *right;
node(int val) : key(val), count(1), size(1), height(1), left(nullptr), right(nullptr) {}
int get_balance() {
return (left ? left->height : 0) - (right ? right->height : 0);
}
void updatesize() {
size = (left ? left->size : 0) + (right ? right->size : 0) + count;
}
void updateheight() {
height = std::max((left ? left->height : 0), (right ? right->height : 0)) + 1;
}
} *root = nullptr;
void rightrotate(node *&p) {
node *l = p->left, *t2 = l->right;
p->left = t2;
l->right = p;
(*p).updateheight();
(*p).updatesize();
(*l).updatesize();
(*l).updateheight();
p = l;
}
void leftrotate(node *&p) {
node *r = p->right, *t2 = r->left;
p->right = t2;
r->left = p;
(*p).updateheight();
(*p).updatesize();
(*r).updatesize();
(*r).updateheight();
p = r;
}
void rebalance(node *&p) {
if (!p) {
return;
} else {
int b = (*p).get_balance();
if (b < 2 && b > -2) {
return;
} else if (b > 1) {
if (p->left->get_balance() < 0) {
leftrotate(p->left);
}
rightrotate(p);
} else {
if (p->right->get_balance() > 0) {
rightrotate(p->right);
}
leftrotate(p);
}
}
}
void insert(int val, node *&p) {
if (!p) {
p = new node(val);
return;
} else if (p->key == val) {
p->count++;
return;
} else if (p->key > val) {
insert(val, p->left);
} else {
insert(val, p->right);
}
p->updatesize();
p->updateheight();
rebalance(p);
}
int kth_element(int k, node *&p) {
if (!p) {
return 0;
} else {
int leftsize = (p->left ? p->left->size : 0);
if (leftsize > k) {
return kth_element(k, p->left);
} else if (leftsize + p->count > k) {
return p->key;
} else {
return kth_element(k - leftsize - p->count, p->right);
}
}
}
public:
void insert(int val) {
insert(val, root);
}
int kth_element(int k) {
return kth_element(k, root);
}
};
}
using namespace std;
tree::AVL_tree box;
int m, n, a[200005], u[200005], i;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> m >> n;
for (int j = 1; j <= m; ++j) {
cin >> a[j];
}
for (int j = 1; j <= n; ++j) {
cin >> u[j];
}
for (int j = 1; j <= m; j++) {
box.insert(a[j]);
if (j >= u[i + 1]) {
cout << box.kth_element(i) << endl;
// cout<<j<<endl;
i++;
}
}
// cout<<i;
return 0;
}
```
by litjohn @ 2024-03-24 12:24:54