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| #pragma once
#include "../memery_management/memery_pool.h"
#include "search_tree.h"
#include "vector.h"
namespace data_structure {
template <class T>
class scapegoat_tree : public search_tree<T> {
struct node {
node *ls, *rs;
int siz, scapegoat;
T key;
};
static const double alpha;
memery_pool<node> pool;
node* root = nullptr;
void copy_self(node*& rt, node* cp) {
if (cp == nullptr) return;
rt = pool.get();
*rt = *cp;
copy_self(rt->ls, cp->ls);
copy_self(rt->rs, cp->rs);
}
void delete_self(node* rt) {
if (rt == nullptr) return;
delete_self(rt->ls);
delete_self(rt->rs);
pool.erase(rt);
}
node* newnode(const T& w) {
node* res = pool.get();
res->ls = res->rs = nullptr;
res->key = w;
res->siz = 1;
res->scapegoat = 0;
return res;
}
void make_list(node* rt, vector<node*>& array) {
if (rt == nullptr) return;
make_list(rt->ls, array);
if (!rt->scapegoat) array.push_back(rt);
make_list(rt->rs, array);
if (rt->scapegoat) pool.erase(rt);
}
void build_dfs(node*& rt, vector<node*>& array, int l, int r) {
if (l > r) {
rt = nullptr;
return;
}
int mid = l + r >> 1;
rt = array[mid];
build_dfs(rt->ls, array, l, mid - 1);
build_dfs(rt->rs, array, mid + 1, r);
maintain(rt);
}
void rebuild(node*& rt) {
vector<node*> array;
make_list(rt, array);
build_dfs(rt, array, 0, array.size() - 1);
}
void maintain(node*& rt) {
int lsiz = rt->ls == nullptr ? 0 : rt->ls->siz;
int rsiz = rt->rs == nullptr ? 0 : rt->rs->siz;
rt->siz = lsiz + rsiz + 1;
if (rt->scapegoat) rt->siz--;
static node** prt = nullptr;
if (lsiz > alpha * rt->siz || rsiz > alpha * rt->siz) prt = &rt;
if (rt == root && prt != nullptr) {
node** tem = prt;
prt = nullptr;
rebuild(*tem);
}
}
void insert(node*& rt, const T& w) {
if (rt == nullptr)
rt = newnode(w);
else if (w < rt->key)
insert(rt->ls, w);
else if (rt->key < w)
insert(rt->rs, w);
else if (rt->scapegoat) {
rt->scapegoat = 0;
}
maintain(rt);
}
node*& search(node*& rt, const T& w) {}
void erase(node*& rt, const T& w) {
if (rt == nullptr) {
return;
} else if (w < rt->key) {
erase(rt->ls, w);
} else if (rt->key < w) {
erase(rt->rs, w);
} else {
rt->scapegoat = 1;
}
maintain(rt);
}
void preorder(node*& rt, void (*f)(const T&)) {
if (rt == nullptr) return;
if (!rt->scapegoat) f(rt->key);
preorder(rt->ls, f);
preorder(rt->rs, f);
}
void midorder(node*& rt, void (*f)(const T&)) {
if (rt == nullptr) return;
midorder(rt->ls, f);
if (!rt->scapegoat) f(rt->key);
midorder(rt->rs, f);
}
public:
scapegoat_tree() { root = nullptr; }
scapegoat_tree(const scapegoat_tree<T>& rhs) { copy_self(root, rhs.root); }
scapegoat_tree<T> operator=(const scapegoat_tree<T>& rhs) {
delete_self(root);
copy_self(root, rhs.root);
return *this;
}
~scapegoat_tree() { delete_self(root); }
void insert(const T& w) { insert(root, w); }
node*& search(const T& w) { return search(root, w); }
void erase(const T& w) { erase(root, w); }
void preorder(void (*f)(const T&)) { preorder(root, f); }
void midorder(void (*f)(const T&)) { midorder(root, f); }
};
template<class T>
const double scapegoat_tree<T>::alpha = 0.7;
}
|