michael/lean2
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add remaining splay tree methods

Browse source 
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-09-24 00:43:08 -07:00
parent 01f5fa59b1
commit b78b2e0585
2 changed files with 174 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
src/tests/util/splay_tree.cpp
View file

@ -60,14 +60,17 @@ void tst1() {
lean_assert(s.contains(3));
lean_assert(s.contains(20));
std::cout << s << "\n";
std::cout << "BEFORE CONSTR\n";
int_splay_tree s2(s);
std::cout << "AFTER CONSTR\n";
std::cout << s2 << "\n";
s.insert(34);
std::cout << s2 << "\n";
std::cout << s << "\n";
std::cout << "END\n";
int const * v = s.find_memoize(11);
lean_assert(*v == 11);
std::cout << s << "\n";
lean_assert(!s.empty());
s.clear();
lean_assert(s.empty());
}
bool operator==(int_set const & v1, int_splay_tree const & v2) {
@ -89,12 +92,13 @@ static void driver(unsigned max_sz, unsigned max_val, unsigned num_ops, double i
int_splay_tree v2;
int_splay_tree v3;
std::mt19937 rng;
size_t acc_sz = 0;
rng.seed(static_cast<unsigned int>(time(0)));
std::uniform_int_distribution<unsigned int> uint_dist;
std::vector<int_splay_tree> copies;
for (unsigned i = 0; i < num_ops; i++) {
acc_sz += v1.size();
double f = static_cast<double>(uint_dist(rng) % 10000) / 10000.0;
if (f < copy_freq) {
copies.push_back(v2);
@ -113,17 +117,26 @@ static void driver(unsigned max_sz, unsigned max_val, unsigned num_ops, double i
v2.insert(a);
v3 = insert(v3, a);
} else {
// TODO(Leo): erase operation for splay_trees
int a = uint_dist(rng) % max_val;
v1.erase(a);
v2.erase(a);
v3 = erase(v3, a);
}
lean_assert(v1 == v2);
lean_assert(v1 == v3);
lean_assert(v1.size() == v2.size());
}
std::cout << "\n";
std::cout << "Copies created: " << copies.size() << "\n";
std::cout << "Average size: " << static_cast<double>(acc_sz) / static_cast<double>(num_ops) << "\n";
}
static void tst2() {
driver(4, 32, 10000, 0.5, 0.01);
driver(4, 10000, 10000, 0.5, 0.01);
driver(16, 16, 10000, 0.5, 0.1);
driver(128, 64, 10000, 0.5, 0.1);
driver(128, 64, 10000, 0.4, 0.1);
driver(128, 1000, 10000, 0.5, 0.5);
driver(128, 1000, 10000, 0.5, 0.01);
}

168
src/util/splay_tree.h
View file

@ -6,6 +6,7 @@ Author: Leonardo de Moura
*/
#pragma once
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include "util/rc.h"
@ -14,7 +15,22 @@ Author: Leonardo de Moura
#include "util/buffer.h"
namespace lean {
/**
\brief Splay trees (see http://en.wikipedia.org/wiki/Splay_tree)
It uses a O(1) copy operation. Different tree can share nodes.
The sharing is thread-safe.
\c CMP is a functional object for comparing values of type T.
It must have a method
<code>
int operator()(T const & v1, T const & v2) const;
</code>
The method must return
- -1 if <tt>v1 < v2</tt>,
- 0 if <tt>v1 == v2</tt>,
- 1 if <tt>v1 > v2</tt>
*/
template<typename T, typename CMP>
class splay_tree : public CMP {
struct node {
@ -183,6 +199,7 @@ class splay_tree : public CMP {
child->inc_ref();
entry const & last = path.back();
node * parent = last.m_node;
lean_assert(!parent->is_shared());
if (last.m_right) {
node::dec_ref(parent->m_right);
parent->m_right = child;
@ -201,24 +218,21 @@ class splay_tree : public CMP {
}
}
public:
splay_tree(CMP const & cmp = CMP()):CMP(cmp), m_ptr(nullptr) {}
splay_tree(splay_tree const & s):CMP(s), m_ptr(s.m_ptr) { node::inc_ref(m_ptr); }
splay_tree(splay_tree && s):CMP(s), m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
~splay_tree() { node::dec_ref(m_ptr); }
splay_tree & operator=(splay_tree const & s) { LEAN_COPY_REF(splay_tree, s); }
splay_tree & operator=(splay_tree && s) { LEAN_MOVE_REF(splay_tree, s); }
bool empty() const { return m_ptr == nullptr; }
void insert(T const & v) {
bool insert_pull(T const & v, bool is_insert) {
static thread_local std::vector<entry> path;
node * n = m_ptr;
bool found = false;
while (true) {
if (n == nullptr) {
if (is_insert) {
n = new node(v);
update_parent(path, n);
} else {
if (path.empty())
return false;
n = path.back().m_node;
path.pop_back();
}
break;
} else {
if (n->is_shared()) {
@ -234,39 +248,159 @@ public:
path.push_back(entry(true, n));
n = n->m_right;
} else {
if (is_insert)
n->m_value = v;
found = true;
break;
}
}
}
splay_to_top(path, n);
m_ptr = n;
lean_assert(check_invariant())
lean_assert(check_invariant());
return found;
}
bool contains(T const & v) const {
bool pull(T const & v) {
return insert_pull(v, false);
}
void pull_max() {
if (!m_ptr) return;
static thread_local std::vector<entry> path;
node * n = m_ptr;
while (true) {
lean_assert(n);
if (n->is_shared()) {
n = new node(*n);
update_parent(path, n);
}
if (n->m_right) {
path.push_back(entry(true, n));
n = n->m_right;
} else {
splay_to_top(path, n);
m_ptr = n;
lean_assert(check_invariant());
return;
}
}
}
static unsigned size(node const * n) {
if (n)
return 1 + size(n->m_left) + size(n->m_right);
else
return 0;
}
splay_tree(splay_tree const & s, node * new_root):CMP(s), m_ptr(new_root) { node::inc_ref(m_ptr); }
public:
splay_tree(CMP const & cmp = CMP()):CMP(cmp), m_ptr(nullptr) {}
splay_tree(splay_tree const & s):CMP(s), m_ptr(s.m_ptr) { node::inc_ref(m_ptr); }
splay_tree(splay_tree && s):CMP(s), m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
~splay_tree() { node::dec_ref(m_ptr); }
/** \brief O(1) copy */
splay_tree & operator=(splay_tree const & s) { LEAN_COPY_REF(splay_tree, s); }
/** \brief O(1) move */
splay_tree & operator=(splay_tree && s) { LEAN_MOVE_REF(splay_tree, s); }
void swap(splay_tree & t) { std::swap(m_ptr, t.m_ptr); }
/** \brief Return true iff this splay tree is empty. */
bool empty() const { return m_ptr == nullptr; }
/** \brief Remove all elements from the splay tree. */
void clear() { node::dec_ref(m_ptr); m_ptr = nullptr; }
/** \brief Return true iff this splay tree and \c t point to the same node */
bool is_eqp(splay_tree const & t) const { return m_ptr == t.m_ptr; }
/** \brief Return the size of the splay tree */
unsigned size() const { return size(m_ptr); }
/** \brief Insert \c v in this splay tree. */
void insert(T const & v) {
insert_pull(v, true);
}
/**
\brief Return a pointer to a value equal to \c v that is stored in this splay tree.
If the splay tree does not contain any value equal to \c v, then return \c nullptr.
\remark <tt>find(v) != nullptr</tt> iff <tt>contains(v)</tt>
*/
T const * find(T const & v) const {
node const * n = m_ptr;
while (true) {
if (n == nullptr)
return false;
return nullptr;
int c = cmp(v, n->m_value);
if (c < 0)
n = n->m_left;
else if (c > 0)
n = n->m_right;
else
return true;
return &(n->m_value);
}
}
/** \brief Return true iff the splay tree contains an element equal to \c v. */
bool contains(T const & v) const {
return find(v);
}
/**
\brief Similar to \c find, but the splay tree is reorganized.
If <tt>find(v)</tt> is invoked after <tt>find_memoize(v)</tt>, then the cost will be O(1).
The idea is to move recently accessed elements close to the root.
*/
T const * find_memoize(T const & v) {
if (pull(v)) {
lean_assert(cmp(m_ptr->m_value, v) == 0);
return &(m_ptr->m_value);
} else {
return nullptr;
}
}
/** \brief Remove \c v from this splay tree. Actually, it removes an element that is equal to \c v. */
void erase(T const & v) {
if (pull(v)) {
lean_assert(cmp(m_ptr->m_value, v) == 0);
splay_tree left(*this, m_ptr->m_left);
splay_tree right(*this, m_ptr->m_right);
if (left.empty()) {
swap(right);
} else if (right.empty()) {
swap(left);
} else {
clear();
left.pull_max();
lean_assert(left.m_ptr->m_right == nullptr);
right.m_ptr->inc_ref();
left.m_ptr->m_right = right.m_ptr;
swap(left);
}
}
}
/** \brief (For debugging) Check whether this splay tree is well formed. */
bool check_invariant() const {
return check_invariant(m_ptr);
}
/**
\brief Copy the contents of this splay tree to the given buffer.
The elements will be stored in increasing order.
*/
void to_buffer(buffer<T> & r) const {
to_buffer(m_ptr, r);
}
/** \brief (For debugging) Display the content of this splay tree. */
friend std::ostream & operator<<(std::ostream & out, splay_tree const & t) {
node::display(out, t.m_ptr);
return out;
@ -274,4 +408,6 @@ public:
};
template<typename T, typename CMP>
splay_tree<T, CMP> insert(splay_tree<T, CMP> & t, T const & v) { splay_tree<T, CMP> r(t); r.insert(v); return r; }
template<typename T, typename CMP>
splay_tree<T, CMP> erase(splay_tree<T, CMP> & t, T const & v) { splay_tree<T, CMP> r(t); r.erase(v); return r; }
}