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| #include <bits/stdc++.h>
using namespace std;
template<class T, size_t size>
struct MemoryPool {
T buf[size], *tail;
T *st[size];
int top;
MemoryPool() : top(0), tail(buf) {}
inline T *alloc() {
return top ? st[--top] : tail++;
}
inline void recycle(T *p) {
st[top++] = p;
}
};
struct ScapegoatTree {
static const double alpha = 0.75;
static const int MAXN = 100010;
struct Node {
Node * ch[2];
int key, size, cover;
bool exist;
inline void update() {
size = ch[0]->size + ch[1]->size + (int)exist, cover = ch[0]->cover + ch[1]->cover + 1;
}
inline bool check(void) {
return ((ch[0]->cover > cover * alpha + 5) || (ch[1]->cover > cover * alpha + 5));
}
};
Node *root, *null;
MemoryPool<Node, MAXN> pool;
Node *newNode(int key) {
Node *p = pool.alloc();
p->ch[0] = p->ch[1] = null, p->size = p->cover = 1, p->exist = true, p->key = key;
return p;
}
inline void travel(Node *p, std::vector<Node *> &v) {
if (p == null) return;
travel(p->ch[0], v);
if (p->exist) v.push_back(p);
else pool.recycle(p);
travel(p->ch[1], v);
}
inline Node *divide(std::vector<Node *> &v, int l, int r) {
if (l >= r) return null;
int mid = l + r >> 1;
Node *p = v[mid];
p->ch[0] = divide(v, l, mid);
p->ch[1] = divide(v, mid + 1, r);
p->update();
return p;
}
inline void rebuild(Node *&p) {
static std::vector<Node *> v;
v.clear(), travel(p, v), p = divide(v, 0, v.size());
}
inline Node **insert(Node *&p, int val) {
if (p == null) {
p = newNode(val);
return &null;
} else {
p->size++, p->cover++;
Node **res = insert(p->ch[val >= p->key], val);
if (p->check()) res = &p;
return res;
}
}
inline void erase(Node *p, int id) {
p->size--;
register int offset = p->ch[0]->size + p->exist;
if (p->exist && id == offset) {
p->exist = false;
return;
} else {
if (id <= offset) erase(p->ch[0], id);
else erase(p->ch[1], id - offset);
}
}
ScapegoatTree() {
null = pool.alloc();
null->ch[0] = null->ch[1] = null;
null->cover = null->size = null->key = 0;
root = null;
}
inline void insert(int val) {
Node **p = insert(root, val);
if (*p != null) rebuild(*p);
}
inline int rank(int val) {
Node *p = root;
register int ans = 1;
while (p != null) {
if (p->key >= val) p = p->ch[0];
else {
ans += p->ch[0]->size + p->exist;
p = p->ch[1];
}
}
return ans;
}
inline int select(int k) {
Node * p = root;
while (p != null) {
if (p->ch[0]->size + 1 == k && p->exist) return p->key;
else if (p->ch[0]->size >= k) p = p->ch[0];
else k -= p->ch[0]->size + p->exist, p = p->ch[1];
}
}
inline void erase(int k) {
erase(root, rank(k));
if (root->size < alpha * root->cover) rebuild(root);
}
inline void eraseByRank(int k) {
erase(root, k);
if (root->size < alpha * root->cover) rebuild(root);
}
};
inline char read(void) {
static char buf[100000], *p1 = buf, *p2 = buf;
if (p1 == p2) {
p2 = (p1 = buf) + fread(buf, 1, 100000, stdin);
if (p1 == p2) return EOF;
}
return *p1++;
}
inline void read(int &x) {
static char c; c = read(); int b = 1;
for (x = 0; !isdigit(c); c = read()) if (c == '-') b = -b;
for (; isdigit(c); x = (x << 1) + (x << 3) + (c ^ '0'), c = read()); x *= b;
}
ScapegoatTree tree;
int n, k, m;
int main(void) {
read(n);
while (n--) {
read(k), read(m);
switch (k) {
case 1: tree.insert(m); break;
case 2: tree.erase(m); break;
case 3: printf("%d\n", tree.rank(m)); break;
case 4: printf("%d\n", tree.select(m)); break;
case 5: printf("%d\n", tree.select(tree.rank(m) - 1)); break;
case 6: printf("%d\n", tree.select(tree.rank(m + 1))); break;
}
}
return 0;
}
|
