Unordered Set
コードについての説明
hash を用いた順序付き集合クラスの実装である. やっていることは こちら の実装と同じ.
もう少し verify を重ねたい気はしている.
コード
template<class _Key, class _Hash, bool DOWNSIZE> class UnorderedSetIterator;
template<class _Key, class _Hash = hash<_Key>, bool DOWNSIZE = false>
class UnorderedSet
{
private:
using iterator = UnorderedSetIterator<_Key, _Hash, DOWNSIZE>;
using aligned_pointer = typename aligned_storage<sizeof(_Key), alignof(_Key)>::type;
friend UnorderedSetIterator<_Key, _Hash, DOWNSIZE>;
struct bucket {
unsigned int _hash;
short int _dist;
bool _last, _end;
aligned_pointer _key_ptr;
bucket() noexcept : _dist(-1), _last(false), _end(false){}
bucket& operator=(const bucket& another) noexcept {
_hash = another._hash, _dist = another._dist, _last = another._last, _end = another._end;
if(!another.empty()){
new(&_key_ptr) _Key(*reinterpret_cast<const _Key*>(&another._key_ptr));
}
return *this;
}
~bucket(){ if(!empty()) key_ptr()->~_Key(); }
inline void clear() noexcept { _dist = -1; }
inline void _delete(){ _dist = -1, key_ptr()->~_Key(); }
inline bool empty() const noexcept { return (_dist == -1); }
inline _Key& key() noexcept {
return *reinterpret_cast<_Key*>(&_key_ptr);
}
inline _Key* key_ptr() noexcept {
return reinterpret_cast<_Key*>(&_key_ptr);
}
inline void new_key(_Key&& key){
new(&_key_ptr) _Key(move(key));
}
};
inline static unsigned int ceilpow2(unsigned int u) noexcept {
if(u == 0u) return 0u;
--u, u |= u >> 1, u |= u >> 2, u |= u >> 4, u |= u >> 8;
return (u | (u >> 16)) + 1;
}
inline static bucket *increment(bucket *cur) noexcept {
for(++cur; !cur->_end; ++cur){
if(!cur->empty()) break;
}
return cur;
}
inline bucket *next_bucket(bucket *cur) const noexcept {
return cur->_last ? _buckets : cur + 1;
}
inline unsigned int make_hash(const _Key& key) const noexcept {
return _Hash()(key);
}
inline float load_rate() const noexcept {
return (float)_data_count / _bucket_count;
}
bucket *insert(bucket *cur, unsigned int hash, short int dist, _Key&& key){
bucket *ret = cur;
bool flag = false;
while(true){
if(cur->empty()){
cur->_hash = hash, cur->_dist = dist, cur->new_key(move(key));
if(!flag) ret = cur, flag = true;
break;
}else if(dist > cur->_dist){
swap(hash, cur->_hash), swap(dist, cur->_dist), swap(key, cur->key());
if(!flag) ret = cur, flag = true;
}
++dist;
cur = next_bucket(cur);
}
return ret;
}
bucket *_find(const _Key& key) const {
unsigned int hash = make_hash(key);
bucket *cur = _buckets + (hash & _mask);
short int dist = 0;
while(dist <= cur->_dist){
if(hash == cur->_hash && key == cur->key()) return cur;
++dist, cur = next_bucket(cur);
}
return _buckets + _bucket_count;
}
template<class Key>
bucket *find_insert(Key&& key){
unsigned int hash = make_hash(key);
bucket *cur = _buckets + (hash & _mask);
short int dist = 0;
while(dist <= cur->_dist){
if(hash == cur->_hash && key == cur->key()) return cur;
++dist, cur = next_bucket(cur);
}
++_data_count;
if(rehash_check()){
cur = _buckets + (hash & _mask), dist = 0;
}
_Key new_key = forward<Key>(key);
return insert(cur, hash, dist, move(new_key));
}
template<typename... Args>
bucket *emplace(Args&&... args){
return find_insert(_Key(forward<Args>(args)...));
}
bucket *backward_shift(bucket *cur, bool next_ret){
bucket *next = next_bucket(cur), *ret = cur;
if(next->_dist < 1) return next_ret ? increment(cur) : cur;
do {
cur->_hash = next->_hash, cur->_dist = next->_dist - 1;
cur->new_key(move(next->key()));
cur = next, next = next_bucket(cur);
}while(next->_dist >= 1);
cur->clear();
return ret;
}
bucket *erase_impl(bucket *cur, bool next_ret){
assert(static_cast<size_t>(cur - _buckets) != _bucket_count);
cur->_delete();
--_data_count;
return backward_shift(cur, next_ret);
}
bucket *erase_itr(bucket *cur, bool next_ret = true){
const _Key key = cur->key();
return erase_impl(rehash_check() ? _find(key) : cur, next_ret);
}
size_t erase_key(const _Key& key){
rehash_check();
bucket *cur = _find(key);
if(static_cast<size_t>(cur - _buckets) == _bucket_count){
return 0;
}else{
erase_impl(cur, false);
return 1;
}
}
bool rehash_check(){
if(_bucket_count == 0){
rehash(1u);
return true;
}else if(load_rate() >= MAX_LOAD_RATE){
rehash(_bucket_count * 2u);
return true;
}else if(DOWNSIZE){
if(load_rate() <= MIN_LOAD_RATE && _bucket_count >= DOWNSIZE_THRESHOLD){
rehash(_bucket_count / 2u);
return true;
}
}
return false;
}
void move_data(bucket *cur){
insert(_buckets + (cur->_hash & _mask), cur->_hash, 0, move(cur->key()));
}
void rehash(unsigned int new_bucket_count){
UnorderedSet new_unordered_set(new_bucket_count);
new_unordered_set._data_count = _data_count;
for(bucket *cur = _buckets; !cur->_end; ++cur){
if(!cur->empty()){
new_unordered_set.move_data(cur);
}
}
swap(*this, new_unordered_set);
}
friend void swap(UnorderedSet& ust1, UnorderedSet& ust2){
swap(ust1._bucket_count, ust2._bucket_count);
swap(ust1._mask, ust2._mask);
swap(ust1._data_count, ust2._data_count);
swap(ust1._buckets, ust2._buckets);
}
private:
unsigned int _bucket_count, _mask, _data_count;
bucket *_buckets;
public:
const float MAX_LOAD_RATE = 0.5f;
const float MIN_LOAD_RATE = 0.1f;
const unsigned int DOWNSIZE_THRESHOLD = 16u;
UnorderedSet(unsigned int bucket_size = 0u)
: _bucket_count(ceilpow2(bucket_size)), _mask(_bucket_count - 1),
_data_count(0u), _buckets(new bucket[_bucket_count + 1]){
if(_bucket_count > 0) _buckets[_bucket_count - 1]._last = true;
else _mask = 0;
_buckets[_bucket_count]._end = true;
}
UnorderedSet(const UnorderedSet& another)
: _bucket_count(another._bucket_count), _mask(another._mask), _data_count(another._data_count){
_buckets = new bucket[_bucket_count + 1u];
for(unsigned int i = 0u; i <= _bucket_count; ++i){
_buckets[i] = another._buckets[i];
}
}
UnorderedSet(UnorderedSet&& another)
: _bucket_count(move(another._bucket_count)), _mask(move(another._mask)),
_data_count(move(another._data_count)), _buckets(another._buckets){
another._buckets = nullptr;
}
UnorderedSet& operator=(const UnorderedSet& another){
delete[] _buckets;
_bucket_count = another._bucket_count;
_mask = another._mask;
_data_count = another._data_count;
_buckets = new bucket[_bucket_count + 1u];
for(unsigned int i = 0u; i <= _bucket_count; ++i){
_buckets[i] = another._buckets[i];
}
return *this;
}
UnorderedSet& operator=(UnorderedSet&& another){
delete[] _buckets;
_bucket_count = move(another._bucket_count);
_mask = move(another._mask);
_data_count = move(another._data_count);
_buckets = another._buckets;
another._buckets = nullptr;
return *this;
}
void allocate(unsigned int element_size){
rehash(ceilpow2(ceil(element_size / MAX_LOAD_RATE) + 1));
}
~UnorderedSet(){ delete[] _buckets; }
friend ostream& operator<< (ostream& os, UnorderedSet& ust) noexcept {
for(_Key& val : ust) os << val << " ";
return os;
}
void clear(){
UnorderedSet new_unordered_set(0u);
swap(*this, new_unordered_set);
}
size_t size() const noexcept { return _data_count; }
size_t bucket_count() const noexcept { return _bucket_count; }
bool empty() const noexcept { return (_data_count == 0); }
iterator begin() noexcept {
return (_buckets->empty() && _bucket_count > 0) ? iterator(increment(_buckets)) : iterator(_buckets);
}
iterator end() noexcept { return iterator(_buckets + _bucket_count); }
iterator find(const _Key& key) const { return iterator(_find(key)); }
size_t count(const _Key& key) const { return (_find(key) != _buckets + _bucket_count); }
iterator insert(const _Key& key){ return iterator(find_insert(key)); }
iterator insert(_Key&& key){ return iterator(find_insert(move(key))); }
template<typename... Args>
iterator emplace(Args&&... args){ return iterator(_emplace(forward<Args>(args)...)); }
size_t erase(const _Key& key){ return erase_key(key); }
iterator erase(const iterator& itr){ return iterator(erase_itr(itr.bucket_ptr)); }
void simple_erase(const _Key& key){ erase_key(key); }
void simple_erase(const iterator& itr){ erase_itr(itr.bucket_ptr, false); }
// DEBUG 用
short int maximum_distance() const noexcept {
short int ret = -1;
for(bucket *cur = _buckets; !cur->_end; ++cur){
ret = max(ret, cur->_dist);
}
return ret;
}
};
template<class _Key, class _Hash, bool DOWNSIZE>
class UnorderedSetIterator {
private:
friend UnorderedSet<_Key, _Hash, DOWNSIZE>;
typename UnorderedSet<_Key, _Hash, DOWNSIZE>::bucket *bucket_ptr;
using iterator_category = forward_iterator_tag;
using value_type = _Key;
using difference_type = ptrdiff_t;
using pointer = _Key*;
using reference = _Key&;
private:
UnorderedSetIterator(typename UnorderedSet<_Key, _Hash, DOWNSIZE>::bucket *_bucket_ptr)
noexcept : bucket_ptr(_bucket_ptr){}
public:
UnorderedSetIterator() noexcept : bucket_ptr(){}
UnorderedSetIterator(const UnorderedSetIterator& itr) noexcept : bucket_ptr(itr.bucket_ptr){}
UnorderedSetIterator& operator=(const UnorderedSetIterator& itr)
& noexcept { return bucket_ptr = itr.bucket_ptr, *this; }
UnorderedSetIterator& operator=(const UnorderedSetIterator&& itr)
& noexcept { return bucket_ptr = itr.bucket_ptr, *this; }
reference operator*() const noexcept { return bucket_ptr->key(); }
pointer operator->() const noexcept { return bucket_ptr->key_ptr(); }
UnorderedSetIterator& operator++() noexcept {
return bucket_ptr = UnorderedSet<_Key, _Hash, DOWNSIZE>::increment(bucket_ptr), *this;
}
UnorderedSetIterator operator++(int) const noexcept {
return UnorderedSetIterator(UnorderedSet<_Key, _Hash, DOWNSIZE>::increment(this->bucket_ptr));
}
bool operator==(const UnorderedSetIterator& itr) const noexcept { return !(*this != itr); };
bool operator!=(const UnorderedSetIterator& itr) const noexcept { return bucket_ptr != itr.bucket_ptr; }
};
コード(高速版)
template<class _Key, class _Hash, bool DOWNSIZE> class UnorderedSetIterator;
template<class _Key, class _Hash = hash<_Key>, bool DOWNSIZE = false>
class UnorderedSet
{
private:
using iterator = UnorderedSetIterator<_Key, _Hash, DOWNSIZE>;
friend UnorderedSetIterator<_Key, _Hash, DOWNSIZE>;
struct bucket {
_Key _key;
short int _dist;
bool _last, _end;
bucket() noexcept : _dist(-1), _last(false), _end(false){}
bucket& operator=(const bucket& another) = default;
~bucket(){ if(!empty()) _key.~_Key(); }
inline void clear() noexcept { _dist = -1; }
inline void _delete(){ _dist = -1, _key.~_Key(); }
inline bool empty() const noexcept { return (_dist == -1); }
};
inline static unsigned int ceilpow2(unsigned int u) noexcept {
if(u == 0u) return 0u;
--u, u |= u >> 1, u |= u >> 2, u |= u >> 4, u |= u >> 8;
return (u | (u >> 16)) + 1;
}
inline static bucket *increment(bucket *cur) noexcept {
for(++cur; !cur->_end; ++cur){
if(!cur->empty()) break;
}
return cur;
}
inline bucket *next_bucket(bucket *cur) const noexcept {
return cur->_last ? _buckets : cur + 1;
}
inline unsigned int make_hash(const _Key& key) const noexcept {
return _Hash()(key);
}
inline float load_rate() const noexcept {
return (float)_data_count / _bucket_count;
}
bucket *insert(bucket *cur, short int dist, _Key&& key){
bucket *ret = cur;
bool flag = false;
while(true){
if(cur->empty()){
cur->_key = move(key), cur->_dist = dist;
if(!flag) ret = cur, flag = true;
break;
}else if(dist > cur->_dist){
swap(key, cur->_key), swap(dist, cur->_dist);
if(!flag) ret = cur, flag = true;
}
++dist;
cur = next_bucket(cur);
}
return ret;
}
bucket *_find(const _Key& key) const {
bucket *cur = _buckets + (make_hash(key) & _mask);
int dist = 0;
while(dist <= cur->_dist){
if(key == cur->_key) return cur;
++dist, cur = next_bucket(cur);
}
return _buckets + _bucket_count;
}
template<class Key>
bucket *find_insert(Key&& key){
unsigned int hash = make_hash(key);
bucket *cur = _buckets + (hash & _mask);
int dist = 0;
while(dist <= cur->_dist){
if(key == cur->_key) return cur;
++dist, cur = next_bucket(cur);
}
++_data_count;
if(rehash_check()){
cur = _buckets + (hash & _mask), dist = 0;
}
_Key new_key = forward<Key>(key);
return insert(cur, dist, move(new_key));
}
template<typename... Args>
bucket *emplace(Args&&... args){
return find_insert(_Key(forward<Args>(args)...));
}
bucket *backward_shift(bucket *cur, bool next_ret){
bucket *next = next_bucket(cur), *ret = cur;
if(next->_dist < 1) return next_ret ? increment(cur) : cur;
do {
cur->_key = next->_key, cur->_dist = next->_dist - 1;
cur = next, next = next_bucket(cur);
}while(next->_dist >= 1);
cur->clear();
return ret;
}
bucket *erase_impl(bucket *cur, bool next_ret){
assert(static_cast<size_t>(cur - _buckets) != _bucket_count);
cur->_delete();
--_data_count;
return backward_shift(cur, next_ret);
}
bucket *erase_itr(bucket *cur, bool next_ret = true){
const _Key key = cur->_key;
return erase_impl(rehash_check() ? _find(key) : cur, next_ret);
}
size_t erase_key(const _Key& key){
rehash_check();
bucket *cur = _find(key);
if(static_cast<size_t>(cur - _buckets) == _bucket_count){
return 0;
}else{
erase_impl(cur, false);
return 1;
}
}
bool rehash_check(){
if(_bucket_count == 0){
rehash(1u);
return true;
}else if(load_rate() >= MAX_LOAD_RATE){
rehash(_bucket_count * 2u);
return true;
}else if(DOWNSIZE){
if(load_rate() <= MIN_LOAD_RATE && _bucket_count >= DOWNSIZE_THRESHOLD){
rehash(_bucket_count / 2u);
return true;
}
}
return false;
}
void move_data(bucket *cur){
insert(_buckets + (make_hash(cur->_key) & _mask), 0, move(cur->_key));
}
void rehash(unsigned int new_bucket_count){
UnorderedSet new_unordered_set(new_bucket_count);
new_unordered_set._data_count = _data_count;
for(bucket *cur = _buckets; !cur->_end; ++cur){
if(!cur->empty()){
new_unordered_set.move_data(cur);
}
}
swap(*this, new_unordered_set);
}
friend void swap(UnorderedSet& ust1, UnorderedSet& ust2){
swap(ust1._bucket_count, ust2._bucket_count);
swap(ust1._mask, ust2._mask);
swap(ust1._data_count, ust2._data_count);
swap(ust1._buckets, ust2._buckets);
}
private:
unsigned int _bucket_count, _mask, _data_count;
bucket *_buckets;
public:
const float MAX_LOAD_RATE = 0.5f;
const float MIN_LOAD_RATE = 0.1f;
const unsigned int DOWNSIZE_THRESHOLD = 16u;
UnorderedSet(unsigned int bucket_size = 0u)
: _bucket_count(ceilpow2(bucket_size)), _mask(_bucket_count - 1),
_data_count(0u), _buckets(new bucket[_bucket_count + 1]){
if(_bucket_count > 0) _buckets[_bucket_count - 1]._last = true;
else _mask = 0;
_buckets[_bucket_count]._end = true;
}
UnorderedSet(const UnorderedSet& another)
: _bucket_count(another._bucket_count), _mask(another._mask), _data_count(another._data_count){
_buckets = new bucket[_bucket_count + 1u];
for(unsigned int i = 0u; i <= _bucket_count; ++i){
_buckets[i] = another._buckets[i];
}
}
UnorderedSet(UnorderedSet&& another)
: _bucket_count(move(another._bucket_count)), _mask(move(another._mask)),
_data_count(move(another._data_count)), _buckets(another._buckets){
another._buckets = nullptr;
}
UnorderedSet& operator=(const UnorderedSet& another){
delete[] _buckets;
_bucket_count = another._bucket_count;
_mask = another._mask;
_data_count = another._data_count;
_buckets = new bucket[_bucket_count + 1u];
for(unsigned int i = 0u; i <= _bucket_count; ++i){
_buckets[i] = another._buckets[i];
}
return *this;
}
UnorderedSet& operator=(UnorderedSet&& another){
delete[] _buckets;
_bucket_count = move(another._bucket_count);
_mask = move(another._mask);
_data_count = move(another._data_count);
_buckets = another._buckets;
another._buckets = nullptr;
return *this;
}
void allocate(unsigned int element_size){
rehash(ceilpow2(ceil(element_size / MAX_LOAD_RATE) + 1));
}
~UnorderedSet(){ delete[] _buckets; }
friend ostream& operator<< (ostream& os, UnorderedSet& ust) noexcept {
for(_Key& val : ust) os << val << " ";
return os;
}
void clear(){
UnorderedSet new_unordered_set(0u);
swap(*this, new_unordered_set);
}
size_t size() const noexcept { return _data_count; }
size_t bucket_count() const noexcept { return _bucket_count; }
bool empty() const noexcept { return (_data_count == 0); }
iterator begin() noexcept {
return (_buckets->empty() && _bucket_count > 0) ? iterator(increment(_buckets)) : iterator(_buckets);
}
iterator end() noexcept { return iterator(_buckets + _bucket_count); }
iterator find(const _Key& key) const { return iterator(_find(key)); }
size_t count(const _Key& key) const { return (_find(key) != _buckets + _bucket_count); }
iterator insert(const _Key& key){ return iterator(find_insert(key)); }
iterator insert(_Key&& key){ return iterator(find_insert(move(key))); }
template<typename... Args>
iterator emplace(Args&&... args){ return iterator(_emplace(forward<Args>(args)...)); }
size_t erase(const _Key& key){ return erase_key(key); }
iterator erase(const iterator& itr){ return iterator(erase_itr(itr.bucket_ptr)); }
void simple_erase(const _Key& key){ erase_key(key); }
void simple_erase(const iterator& itr){ erase_itr(itr.bucket_ptr, false); }
// DEBUG 用
short int maximum_distance() const noexcept {
short int ret = -1;
for(bucket *cur = _buckets; !cur->_end; ++cur){
ret = max(ret, cur->_dist);
}
return ret;
}
};
template<class _Key, class _Hash, bool DOWNSIZE>
class UnorderedSetIterator {
private:
friend UnorderedSet<_Key, _Hash, DOWNSIZE>;
typename UnorderedSet<_Key, _Hash, DOWNSIZE>::bucket *bucket_ptr;
using iterator_category = forward_iterator_tag;
using value_type = _Key;
using difference_type = ptrdiff_t;
using pointer = _Key*;
using reference = _Key&;
private:
UnorderedSetIterator(typename UnorderedSet<_Key, _Hash, DOWNSIZE>::bucket *_bucket_ptr)
noexcept : bucket_ptr(_bucket_ptr){}
public:
UnorderedSetIterator() noexcept : bucket_ptr(){}
UnorderedSetIterator(const UnorderedSetIterator& itr) noexcept : bucket_ptr(itr.bucket_ptr){}
UnorderedSetIterator& operator=(const UnorderedSetIterator& itr)
& noexcept { return bucket_ptr = itr.bucket_ptr, *this; }
UnorderedSetIterator& operator=(const UnorderedSetIterator&& itr)
& noexcept { return bucket_ptr = itr.bucket_ptr, *this; }
reference operator*() const noexcept { return bucket_ptr->_key; }
pointer operator->() const noexcept { return &(bucket_ptr->_key); }
UnorderedSetIterator& operator++() noexcept {
return bucket_ptr = UnorderedSet<_Key, _Hash, DOWNSIZE>::increment(bucket_ptr), *this;
}
UnorderedSetIterator operator++(int) const noexcept {
return UnorderedSetIterator(UnorderedSet<_Key, _Hash, DOWNSIZE>::increment(this->bucket_ptr));
}
bool operator==(const UnorderedSetIterator& itr) const noexcept { return !(*this != itr); };
bool operator!=(const UnorderedSetIterator& itr) const noexcept { return bucket_ptr != itr.bucket_ptr; }
};
verify 用の問題
AOJ : Set - Set: Delete 提出コード 提出コード(高速版)