C++ 哈希表 线性探测 二次探测 哈希桶
Posted
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了C++ 哈希表 线性探测 二次探测 哈希桶相关的知识，希望对你有一定的参考价值。
#pragma once #include<iostream>//含一次探测 二次探测 #include<vector> #include<math.h> using namespace std; enum Status { EXIST, EMPTY, DELET, }; template <class K,class V> //key/value形式结构体 struct KV { K _key; V _value; KV(const K& key = K(), const V& value = V()) :_key(key) , _value(value) {} }; template <class K, class V> class HashTable { public: KV<K,V>* _tables; size_t _size; size_t _capacity; Status* _status; public: HashTable() :_tables(NULL) ,_size(0) , _capacity(0) , _status(NULL) {} void Insert(const K& key , const V& value ) { if (_capacity == 0 || _size * 10 / _capacity > 7) { if(!_IncreaseCapacity()) cout<<"线性探测散列表已满"<<endl; } size_t i = _HashFanction1(key); do { if (key == _tables[i]._key&&_status[i]==EXIST) break; if (_status[i] != EXIST) { _tables[i]._key = key; _tables[i]._value = value; _status[i] = EXIST; ++_size; break; } else if (++i >= _capacity) i = 0; } while (1); } void Insert2(const K& key, const V& value) { if (_capacity == 0 || _size * 10 / _capacity > 7) { if (!_IncreaseCapacity()) cout << "线性探测散列表已满" << endl; } int count = 0;//二次探测的计数器 size_t i = _HashFanction2(key,count); do { if (i<0) i = _capacity + i; if (key == _tables[i]._key&&_status[i] == EXIST) break; if (_status[i] != EXIST) { _tables[i]._key = key; _tables[i]._value = value; _status[i] = EXIST; ++_size; break; } else i = _HashFanction2(key, i); } while (1); } int Find(const K& key) { size_t i = _HashFanction1(key); size_t j = i; do { if (_status[i] == EXIST&&key==_tables[i]._key) { return i; } else if (++i >= _capacity) i = 0; } while (i!=j); return -1; } void Remove(const K& key) { size_t i = _HashFanction1(key); size_t j = i; do { if (_status[i] == EXIST&&key == _tables[i]._key) { _status[i] = DELET; break; } else if (++i >= _capacity) i = 0; } while (i != j); } void print() { size_t i = 0; for (; i < _capacity; ++i) { printf("[%d] K: %d V: %d S: %d \n",i, _tables[i]._key, _tables[i]._value, _status[i]); } } protected: size_t _HashFanction1(const K& key)//一次探测 （线性探测） { return key%_capacity; } int _HashFanction2(const K& key,const int i)//二次次探测 （防止数据积累在一块内存） { return (key+(int)pow(-1,i)*i*i)%_capacity; } bool _IncreaseCapacity() { const int _PrimeSize = 28;//素数表 static const unsigned long _PrimeList[_PrimeSize] = { 53ul, 97ul, 193ul, 389ul, 769ul, 1543ul, 3079ul, 6151ul, 12289ul, 24593ul, 49157ul, 98317ul, 196613ul, 393241ul, 786433ul, 1572869ul, 3145739ul, 6291469ul, 12582917ul, 25165843ul, 50331653ul, 100663319ul, 201326611ul, 402653189ul, 805306457ul, 1610612741ul, 3221225473ul, 4294967291ul }; for (int i = 0; i < _PrimeSize; ++i) { if (_PrimeList[i]>_capacity) { size_t newCapacity = _PrimeList[i]; HashTable<K, V> newHash; newHash._tables = new KV<K,V>[newCapacity]; newHash._status = new Status[newCapacity]; newHash._capacity=_PrimeList[i]; for (size_t j = 0; j < newCapacity; ++j) { if (_status&&j<_capacity&&_status[j] == EXIST) { //newHash.Insert(_tables[j]._key, _tables[j]._value);//一次探测的增容调一次探测的插入函数 newHash.Insert2(_tables[j]._key, _tables[j]._value);//二次探测。。。。。。 } else { newHash._status[j] = EMPTY; newHash._tables[j]._key = 0; newHash._tables[j]._value = 0; } } swap(_tables, newHash._tables); swap(newHash._status,_status); swap(newHash._capacity, _capacity); return true; } } return false; } }; #pragma once #include<iostream>//哈希桶 #include<vector> #include<math.h> #include<string> using namespace std; template <class K> class GetKey { public: size_t operator()(const K& key) { return key; } }; static size_t BKDRHash(const char * str) { unsigned int seed = 131; // 31 131 1313 13131 131313 unsigned int hash = 0; while (*str) { hash = hash * seed + (*str++); } return (hash & 0x7FFFFFFF); } template <> class GetKey<string> { public: size_t operator()(const string & key) { return BKDRHash(key.c_str()); } }; template <class K,class V> //key/value形式结构体 struct KeyValue { K _key; V _value; KeyValue<K, V>* _next; KeyValue(const K& key = K(), const V& value = V()) :_key(key) , _value(value) , _next(NULL) {} }; template <class K, class V> class HashBucket { public: vector<KeyValue<K, V>*> _tables; size_t _size; public: HashBucket() :_size(0) {} void Insert(const K& key , const V& value ) { if (_tables.capacity()==0|| _size * 10 / _tables.capacity() > 7) { if(!_IncreaseCapacity()) cout<<"线性探测散列表已满"<<endl; } size_t i = _HashFanction1(key); KeyValue<K, V>* cur = _tables[i]; if (cur == NULL) _tables[i] = new KeyValue<K, V>(key, value); else { while (cur) { if (cur->_key == key) return; else if (cur->_next == NULL) break; else cur = cur->_next; } cur->_next = new KeyValue<K, V>(key, value); } ++_size; } int Find(const K& key) { size_t i = _HashFanction1(key); KeyValue<K, V>* cur = _tables[i]; while (cur) { if (cur->_key == key) return i; cur = cur->_next; } return -1; } void Remove(const K& key) { size_t i = _HashFanction1(key); KeyValue<K, V> * cur =_tables[i]; KeyValue<K, V> * prev = NULL; while (cur) { if (cur->_key == key) { if (prev) { prev->_next = cur->_next; } else _tables[i] = NULL; delete cur; return; } prev = cur; cur = cur->_next; } } void print() { size_t i = 0; for (; i < _tables.capacity(); ++i) { KeyValue<K, V>* cur = _tables[i]; if (cur == NULL) //printf("[%d]:K= %d V= %d ->", i, -1,-1); cout<< "[" << i << "] "<< -1 << " " << -1 << " " << "->"; while (cur) { //printf("[%d]:K= %d V= %d ", i, cur->_key,cur->_value); cout << "[" << i << "] "<< _tables[i]->_key << " " << _tables[i]->_value << " " << "->"; cout << "->"; cur = cur->_next; } cout <<" NULL"<<endl; } } protected: size_t _GetKey(const K& key) { return GetKey<K>()(key); } size_t _HashFanction1(const K& key)//一次探测 （线性探测） { size_t k = _GetKey(key); return k%_tables.capacity(); } bool _IncreaseCapacity() { const int _PrimeSize = 28; static const unsigned long _PrimeList[_PrimeSize] = { 53ul, 97ul, 193ul, 389ul, 769ul, 1543ul, 3079ul, 6151ul, 12289ul, 24593ul, 49157ul, 98317ul, 196613ul, 393241ul, 786433ul, 1572869ul, 3145739ul, 6291469ul, 12582917ul, 25165843ul, 50331653ul, 100663319ul, 201326611ul, 402653189ul, 805306457ul, 1610612741ul, 3221225473ul, 4294967291ul }; for (int i = 0; i < _PrimeSize; ++i) { if (_PrimeList[i]>_tables.size()) { size_t newCapacity = _PrimeList[i]; vector<KeyValue<K, V>*> newtables; newtables.resize(newCapacity, 0); for (size_t j = 0; j < _tables.capacity(); ++j) { KeyValue<K, V>* cur = _tables[j]; while (cur) { size_t k = _HashFanction1(cur->_key); KeyValue<K, V>* tmp = cur; KeyValue<K, V>* tmp2 = newtables[k]; if (tmp2 = NULL) { newtables[i] = cur; break; } while (tmp2->_next) { tmp2->_next = cur; } tmp->_next = cur; cur->_next = NULL; _tables[j] = tmp; cur = tmp; } } swap(newtables, _tables); } return true; } return false; } }; #include"hashtable.hpp" //测试用例 #include"hashbucket.hpp" using namespace std; void test() { HashTable<int, int> h1; for (int i = 0; i <30;++i) h1.Insert(i, i); h1.Insert(100,1); h1.Insert(170, 3); h1.Insert(223, 5); h1.Insert(56, 7); h1.Insert(550,9); h1.print(); cout<<h1.Find(223)<<endl; cout << h1.Find(224) << endl; h1.Remove(56); h1.Remove(58); h1.print(); } void test2() { HashTable<int, int> h1; for (int i = 0; i < 30;++i) h1.Insert(i, i); h1.Insert2(100, 1); h1.Insert2(170, 3); h1.Insert2(223, 5); h1.Insert2(56, 7); h1.Insert2(550, 9); h1.print(); cout << h1.Find(223) << endl; cout << h1.Find(224) << endl; h1.Remove(56); h1.Remove(58); h1.print(); } void test3() { HashBucket<int, int> h1; h1.Insert(1,1); h1.Insert(3, 3); h1.Insert(5, 5); h1.Insert(7, 7); h1.Insert(54, 54); h1.Insert(107, 107); for (int i = 0; i < 99;i+=2) h1.Insert(i, i); h1.print(); cout<<h1.Find(1)<<endl; cout<<h1.Find(107)<<endl; cout << h1.Find(5) << endl; h1.Remove(54); h1.print(); } void test4() { HashBucket<string, string> h1; h1.Insert("裴培华", "帅哥"); h1.Insert("农文彤", "大屌"); h1.Insert("鸭仔", "舎宝"); h1.Insert("童坤坤", "学霸"); h1.print(); cout<<h1.Find("裴培华")<<endl; h1.Remove("农文彤"); h1.print(); } int main() { //test(); //test2(); //test3(); test4(); return 0; }
以上是关于C++ 哈希表 线性探测 二次探测 哈希桶的主要内容，如果未能解决你的问题，请参考以下文章