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#104. 普通平衡树

https://loj.ac/s/1496864
This commit is contained in:
Baoshuo Ren 2022-07-01 21:35:25 +08:00
parent 9b2b21aec6
commit ab77c54b7f
Signed by: baoshuo
GPG Key ID: 00CB9680AB29F51A

View File

@ -1,172 +1,323 @@
#include <iostream>
#include <cstdlib>
#include <limits>
using std::cin;
using std::cout;
#define endl '\n'
const char endl = '\n';
const int N = 1e5 + 5;
class Treap {
template <typename T>
class Splay {
private:
struct node {
node *left, *right;
int size, val, key;
T value;
node *lchild, *rchild, *parent, **root;
std::size_t size, count;
node()
: left(nullptr),
right(nullptr),
size(1),
val(0),
key(rand()) {}
: value(0), lchild(nullptr), rchild(nullptr), parent(nullptr), root(nullptr), size(0), count(0) {}
node(int _val)
: left(nullptr),
right(nullptr),
size(1),
val(_val),
key(rand()) {}
node(const T &_value, node *_parent, node **_root)
: value(_value), lchild(nullptr), rchild(nullptr), parent(_parent), root(_root), size(1), count(1) {}
~node() {
delete left, right;
if (lchild != nullptr) delete lchild;
if (rchild != nullptr) delete rchild;
}
inline void pushup() {
this->size = 1;
if (this->left != nullptr) this->size += this->left->size;
if (this->right != nullptr) this->size += this->right->size;
node *&child(unsigned int x) {
return !x ? lchild : rchild;
}
} *root = nullptr;
int getNodeSize(node *);
node *find(node *, int);
std::pair<node *, node *> split(node *, int);
std::pair<node *, node *> splitByValue(node *, int);
node *merge(node *, node *);
int _getRank(node *, int);
unsigned int relation() const {
// 如果当前节点是其父亲节点的左儿子则返回 0否则返回 1
return this == parent->lchild ? 0 : 1;
}
// 左儿子大小
std::size_t lsize() const {
return lchild == nullptr ? 0 : lchild->size;
}
// 右儿子大小
std::size_t rsize() const {
return rchild == nullptr ? 0 : rchild->size;
}
// 上传信息
void pushup() {
size = lsize() + count + rsize();
}
// 旋转
void rotate() {
node *old = parent;
unsigned int x = relation();
if (old->parent != nullptr) {
old->parent->child(old->relation()) = this;
}
parent = old->parent;
old->child(x) = child(x ^ 1);
if (child(x ^ 1) != nullptr) {
child(x ^ 1)->parent = old;
}
child(x ^ 1) = old;
old->parent = this;
old->pushup();
pushup();
if (parent == nullptr) *root = this;
}
// Splay
void splay(node *target = nullptr) {
while (parent != target) {
if (parent->parent == target) { // 父节点是目标节点
rotate();
} else if (relation() == parent->relation()) { // 关系相同
parent->rotate();
rotate();
} else {
rotate();
rotate();
}
}
}
// 前驱:左子树的最右点
node *predecessor() {
node *pred = lchild;
while (pred->rchild != nullptr) {
pred = pred->rchild;
}
return pred;
}
// 后继:右子树的最左点
node *successor() {
node *succ = rchild;
while (succ->lchild != nullptr) {
succ = succ->lchild;
}
return succ;
}
} * root;
// 插入(内部函数)
node *_insert(const T &value) {
node **target = &root, *parent = nullptr;
while (*target != nullptr && (*target)->value != value) {
parent = *target;
parent->size++;
// 根据大小向左右子树迭代
if (value < parent->value) {
target = &parent->lchild;
} else {
target = &parent->rchild;
}
}
if (*target == nullptr) {
*target = new node(value, parent, &root);
} else {
(*target)->count++;
(*target)->size++;
}
(*target)->splay();
return root;
}
// 查找指定的值对应的节点
node *find(const T &value) {
node *node = root; // 从根节点开始查找
while (node != nullptr && value != node->value) {
if (value < node->value) {
node = node->lchild;
} else {
node = node->rchild;
}
}
if (node != nullptr) {
node->splay();
}
return node;
}
// 删除
void erase(node *u) {
if (u == nullptr) return;
if (u->count > 1) { // 存在重复的数
u->splay();
u->count--;
u->size--;
return;
}
node *pred = u->predecessor(),
*succ = u->successor();
pred->splay();
succ->splay(pred);
delete succ->lchild;
succ->lchild = nullptr;
succ->pushup();
pred->pushup();
}
public:
Treap()
: root(nullptr) {}
void insert(int);
void erase(int);
int getRank(int);
int getKth(int);
} tree;
inline int Treap::getNodeSize(Treap::node *node) {
return node == nullptr ? 0 : node->size;
}
std::pair<Treap::node *, Treap::node *> Treap::split(Treap::node *p, int k) {
if (p == nullptr) return std::make_pair(nullptr, nullptr);
std::pair<Treap::node *, Treap::node *> o;
if (k <= this->getNodeSize(p->left)) {
o = this->split(p->left, k);
p->left = o.second;
p->pushup();
o.second = p;
} else {
o = this->split(p->right, k - this->getNodeSize(p->left) - 1);
p->right = o.first;
p->pushup();
o.first = p;
Splay()
: root(nullptr) {
insert(std::numeric_limits<T>::min());
insert(std::numeric_limits<T>::max());
}
return o;
}
std::pair<Treap::node *, Treap::node *> Treap::splitByValue(Treap::node *p, int val) {
if (p == nullptr) return std::make_pair(nullptr, nullptr);
std::pair<Treap::node *, Treap::node *> o;
if (p->val < val) {
o = this->splitByValue(p->right, val);
p->right = o.first;
p->pushup();
o.first = p;
} else {
o = this->splitByValue(p->left, val);
p->left = o.second;
p->pushup();
o.second = p;
~Splay() {
delete root;
}
return o;
}
Treap::node *Treap::merge(Treap::node *x, Treap::node *y) {
if (x == nullptr) return y;
if (y == nullptr) return x;
if (x->key > y->key) {
x->right = this->merge(x->right, y);
x->pushup();
return x;
// 插入
void insert(const T &value) {
_insert(value);
}
y->left = this->merge(x, y->left);
y->pushup();
return y;
}
Treap::node *Treap::find(Treap::node *p, int val) {
if (p == nullptr) return nullptr;
if (p->val == val) return p;
if (p->val > val) return this->find(p->left, val);
return this->find(p->right, val);
}
// 删除
void erase(const T &value) {
node *node = find(value);
void Treap::insert(int val) {
auto o = this->splitByValue(this->root, val);
o.first = this->merge(o.first, new Treap::node(val));
this->root = this->merge(o.first, o.second);
}
if (node == nullptr) return;
void Treap::erase(int val) {
auto o = this->splitByValue(this->root, val);
auto t = o;
if (this->find(o.second, val) != nullptr) {
t = this->split(o.second, 1);
delete t.first;
erase(node);
}
this->root = this->merge(o.first, t.second);
}
int Treap::_getRank(Treap::node *p, int val) {
if (p == nullptr) return 1;
if (val <= p->val) return this->_getRank(p->left, val);
return this->getNodeSize(p->left) + 1 + this->_getRank(p->right, val);
}
// 排名
unsigned int rank(const T &value) {
node *node = find(value);
inline int Treap::getRank(int val) {
return this->_getRank(this->root, val);
}
if (node == nullptr) {
node = _insert(value);
// 此时 node 已经成为根节点,直接计算即可
int res = node->lsize(); // 由于「哨兵」的存在,此处无需 -1
erase(node);
int Treap::getKth(int k) {
auto x = this->split(this->root, k - 1);
auto y = this->split(x.second, 1);
Treap::node *o = y.first;
this->root = this->merge(x.first, this->merge(y.first, y.second));
return o == nullptr ? -1 : o->val;
}
return res;
}
int n, op, x;
// 此时 node 已经成为根节点,直接计算即可
return node->lsize();
}
// 选择
const T &select(int k) {
node *node = root;
while (k < node->lsize() || k >= node->lsize() + node->count) {
if (k < node->lsize()) { // 所需的节点在左子树中
node = node->lchild;
} else {
k -= node->lsize() + node->count;
node = node->rchild;
}
}
node->splay();
return node->value;
}
// 前驱
const T &predecessor(const T &value) {
node *node = find(value);
if (node == nullptr) {
node = _insert(value);
const T &result = node->predecessor()->value;
erase(node);
return result;
}
return node->predecessor()->value;
}
// 后继
const T &successor(const T &value) {
node *node = find(value);
if (node == nullptr) {
node = _insert(value);
const T &result = node->successor()->value;
erase(node);
return result;
}
return node->successor()->value;
}
};
int n;
Splay<int> tree;
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
while (n--) {
for (int i = 1; i <= n; i++) {
int op, x;
cin >> op >> x;
if (op == 1) {
tree.insert(x);
} else if (op == 2) {
tree.erase(x);
} else if (op == 3) {
cout << tree.getRank(x) << endl;
} else if (op == 4) {
cout << tree.getKth(x) << endl;
} else if (op == 5) {
cout << tree.getKth(tree.getRank(x) - 1) << endl;
} else {
cout << tree.getKth(tree.getRank(x + 1) /* + 1*/) << endl;
switch (op) {
case 1: {
tree.insert(x);
break;
}
case 2: {
tree.erase(x);
break;
}
case 3: {
cout << tree.rank(x) << endl;
break;
}
case 4: {
cout << tree.select(x) << endl;
break;
}
case 5: {
cout << tree.predecessor(x) << endl;
break;
}
case 6: {
cout << tree.successor(x) << endl;
break;
}
}
}
return 0;
}