代码如下:

#include <iostream>
#include <vector>
using namespace std;template<typename K,typename V,typename KeyOfValue>
class HashTable;//声明template<typename V>
struct HashNode
{typedef HashNode<V> Node;V _val;Node * _next;HashNode(const V & val):_val(val),_next(nullptr){}
};template<typename K,typename V,typename KeyOfValue>
struct HashIterator
{typedef HashNode<V> Node;typedef HashIterator<K, V, KeyOfValue> Self;typedef HashTable<K, V, KeyOfValue>HT;Node *_node;HT * _hPtr;HashIterator(Node *node,HT *hPtr):_node(node),_hPtr(hPtr){}V &operator*(){return _node->_val;}V *operator->(){return &_node->_val;}bool operator!=(const Self & it){return _node != it._node;}Self & operator++(){if (_node->_next){_node = _node->_next;}else{KeyOfValue kov;size_t idx = kov(_node->_val) % _hPtr->_ht.size();++idx;for (; idx < _hPtr->_ht.size(); idx++){if (_hPtr->_ht[idx]){_node = _hPtr->_ht[idx];break;}}if (idx == _hPtr->_ht.size()) _node = nullptr;}return *this;}};template<typename K,typename V,typename KeyOfValue>
class HashTable
{
public:typedef HashIterator<K, V, KeyOfValue> iterator;typedef HashNode<V> Node;template<typename K,typename V,typename KeyOfValue>friend struct HashIterator;HashTable(int n = 10):_ht(n),_size(0){}iterator begin(){for (size_t i = 0; i < _ht.size(); i++){if (_ht[i]){return iterator(_ht[i], this);}}return iterator(nullptr, this);}iterator end(){return iterator(nullptr, this);}pair<iterator, bool> insert(const V & val){//0.检查容量checkCapacity();KeyOfValue kov;//1.计算hash位置int idx = kov(val) % _ht.size();//2.查找Node *cur = _ht[idx];while (cur){if (kov(cur->_val) == kov(val)) return make_pair(iterator(cur, this), false);cur = cur->_next;}//3.插入--头插cur = new Node(val);cur->_next = _ht[idx];_ht[idx] = cur;++_size;return make_pair(iterator(cur, this), true);}void checkCapacity(){if (_size == _ht.size()){int newC = _size == 0 ? 10 : 2 * _size;vector<Node *>newHt(newC);KeyOfValue kov;for (size_t i = 0; i < _ht.size(); i++){Node *cur = _ht[i];while (cur){Node *next = cur->_next;int idx = kov(cur->_val) % newHt.size();cur->_next = newHt[idx];newHt[idx] = cur;cur = next;}_ht[i] = nullptr;}swap(_ht, newHt);}}private:vector<Node *> _ht;int _size;
};template<typename K>
class UnorderedSet
{struct SetKeyOfValue{const K & operator()(const K & key){return key;}};public:typedef typename  HashTable<K, K, SetKeyOfValue>::iterator iterator;pair<iterator, bool> insert(const K& key){return _ht.insert(key);}iterator begin(){return _ht.begin();}iterator end(){return _ht.end();}private:HashTable<K, K, SetKeyOfValue> _ht;
};template<typename K,typename V>
class UnorderedMap
{struct MapKeyOfValue{const K& operator()(const pair<K, V> & val){return val.first;}};public:typedef typename HashTable<K, pair<K, V>, MapKeyOfValue>::iterator iterator;pair<iterator, bool > insert(const pair<K, V> & val){return _ht.insert(val);}iterator begin() {return _ht.begin();}iterator end(){return _ht.end();}V & operator[](const K& key){pair<iterator, bool> ret = _ht.insert(make_pair(key, V()));return ret.first->second;}private:HashTable<K, pair<K, V>, MapKeyOfValue> _ht;
};int main()
{UnorderedSet<int>s;s.insert(1);s.insert(123);s.insert(123412);s.insert(12);s.insert(1132);s.insert(1131);s.insert(436);s.insert(786);s.insert(13);s.insert(7965);s.insert(7653);s.insert(645);s.insert(324);UnorderedSet<int>::iterator it1 = s.begin();while (it1 != s.end()){cout << *it1 << " ";++it1;}cout << endl;for (const auto & e : s){cout << e << " ";}cout << endl;UnorderedMap<int, int>m;m.insert(make_pair(1, 1));m[2] = 2;m[3] = 3;UnorderedMap<int, int>::iterator it2 = m.begin();while (it2 != m.end()){cout << it2->first << "--->" << it2->second << endl;++it2;}cout << "--------------------" << endl;m[2] = 20;for (auto & p : m){cout << p.first << "--->" << p.second << endl;}return 0;
}

测试结果: