#pragma once
#include <vector>

//template<class K>
//struct HashFunc
//{
//	size_t operator()(const K& key)
//	{
//		return (size_t)key;
//	}
//};
//
namespace HashBucket_realize
{
	template<class K, class V>
	struct HashNode
	{
		HashNode<K, V>* _next;
		pair<K, V> _kv;

		HashNode(const pair<K, V>& kv)
			:_next(nullptr)
			,_kv(kv)
		{}
	};

	template<class K, class V, class Hash = HashFunc<K>>
	class HashBucket
	{
		typedef HashNode<K, V> Node;
	public:
		HashBucket()
			:_n(0)
		{
			//_tables.resize(10);
			_tables.resize(__stl_next_prime(0));
		}

		~HashBucket()
		{
			for (size_t i = 0; i < _tables.size(); i++)
			{
				Node* cur = _tables[i];
				while (cur)
				{
					Node* next = cur->_next;
					delete cur;
					cur = next;
				}
				_tables[i] = nullptr;
			}
		}

		bool Insert(const pair<K, V>& kv)
		{
			if (Find(kv.first))
				return false;

			if (_n == _tables.size())
			{
				/*HashBucket<K, V, Hash> newHB;
				newHB._tables.resize(_tables.size() * 2);
				for (auto cur : _tables)
				{
					while (cur)
					{
						newHB.Insert(cur->_kv);
						cur = cur->_next;
					}
				}
				_tables.swap(newHB._tables);*/


				vector<Node*> newTables;
				//newTables.resize(2 * _tables.size(), nullptr);
				newTables.resize(__stl_next_prime(_tables.size()), nullptr);
				for (size_t i = 0; i < _tables.size(); i++)
				{
					Node* cur = _tables[i];
					while (cur)
					{
						Node* next = cur->_next; // 保存下一节点的地址
						size_t hashi = Hash()(cur->_kv.first) % newTables.size();
						// 头插到新表
						cur->_next = newTables[hashi]; // 这句没写
						newTables[hashi] = cur;
						cur = next;
					}
					_tables[i] = nullptr; // 
				}
				_tables.swap(newTables);
			}
			size_t hashi = Hash()(kv.first) % _tables.size();
			Node* newNode = new Node(kv); // 需要写构造函数，不然无法构造newNode
			newNode->_next = _tables[hashi];
			_tables[hashi] = newNode;
			++_n;

			return true;
		}

		Node* Find(const K& key)
		{
			size_t hashi = Hash()(key) % _tables.size();
			Node* cur = _tables[hashi];
			while (cur)
			{
				if (cur->_kv.first == key)
				{
					return cur;
				}
				else
				{
					cur = cur->_next;
				}
			}
			return nullptr; // 
		}

		bool Erase(const K& key)
		{
			size_t hashi = Hash()(key) % _tables.size();
			Node* prev = nullptr;
			Node* cur = _tables[hashi];
			while (cur)
			{
				if (cur->_kv.first == key)
				{
					if (cur == _tables[hashi]) // 特殊情况:待删节点就是_tables[hashi]
					{
						_tables[hashi] = cur->_next;
					}
					else
					{
						prev->_next = cur->_next;
					}
					delete cur;
					--_n;
					return true;
				}
				else
				{
					prev = cur;
					cur = cur->_next;
				}
			}
			return false;
		}

		inline unsigned long __stl_next_prime(unsigned long n)
		{
			static const int __stl_num_primes = 28;
			static const unsigned long __stl_prime_list[__stl_num_primes] =
			{
				53, 97, 193, 389, 769,
				1543, 3079, 6151, 12289, 24593,
				49157, 98317, 196613, 393241, 786433,
				1572869, 3145739, 6291469, 12582917, 25165843,
				50331653, 100663319, 201326611, 402653189, 805306457,
				1610612741, 3221225473, 4294967291
			};

			for (int i = 0; i < __stl_num_primes; ++i)
			{
				if (__stl_prime_list[i] > n)
				{
					return __stl_prime_list[i];
				}
			}

			return __stl_prime_list[__stl_num_primes - 1];
		}

	private:
		vector<Node*> _tables; // 指针数组
		size_t _n;
	};

	void TestHB1()
	{
		HashBucket<int, int> hb;
		int a[] = {18, 8, 7, 27, 57, 3, 38, 18, 17, 88, 38, 28};
		for (auto e : a)
		{
			hb.Insert(make_pair(e, e));
		}

		hb.Insert(make_pair(5, 5));

		cout << hb.Find(7) << endl;
		cout << hb.Find(8) << endl;

		hb.Erase(7);
		cout << hb.Find(7) << endl;

	}

	void TestHB2()
	{
		string arr[] = { "苹果", "西瓜", "香蕉", "草莓", "苹果", "西瓜",
			"苹果", "苹果", "西瓜", "苹果", "香蕉", "苹果", "香蕉" };

		HashBucket<string, int> countHT;
		//HashTable<string, int> countHT;
		for (auto& e : arr)
		{
			auto ret = countHT.Find(e);
			if (ret)
			{
				ret->_kv.second++;
			}
			else
			{
				countHT.Insert(make_pair(e, 1));
			}
		}
	}
}