[数据结构与算法]C++ 手写 unordered_map 实现

insert(Key,Value)插入映射
可以直接通过 [] 插入或查询
虽然写的是泛型，但暂时不知道非整形的类型要怎么获取hash数，回头学下

#include<iostream>
#include<string>
using namespace std;
#ifndef UNORDEREDMAP
#define UNORDEREDMAP
template<typename Key, typename Value>
class hashNode
{
public:
	Key key;
	Value value;
	hashNode* next;
	hashNode(Key _key,Value _value):key(_key),value(_value),next(NULL){}
	hashNode operator = (Value value)
	{
		this.value = value;
	}
	hashNode operator == (const hashNode& c)
	{
		return c.value == value;
	}
	hashNode operator == (Value vv)
	{
		return value == vv;
	}
};
template<typename Key,typename Value>
class unordered_map
{
public:
	int hash(Key key) const
	{
		return (key * 123 + 3) % this_size;
	}
	explicit unordered_map(int sz) :this_size(sz)
	{
		table = new hashNode<Key, Value> * [sz];
		for (int i = 0;i < sz;i++) table[i] = NULL;
	}
	Value& operator [] (Key key)
	{
		int pos = hash(key);
		hashNode<Key, Value>* now = table[pos];
		while (now)
		{
			if (now->key == key) return now->value;
			now = now->next;
		}
		throw "123";
	}
	void insert(Key key, Value value)
	{
		int pos = hash(key);
		hashNode<Key, Value>* now = table[pos];
		while (now)
		{
			if (now->key == key) { now->value = value; return; }
			now = now->next;
		}
		hashNode<Key, Value>* tmp = new hashNode<Key, Value>(key, value);
		tmp->next = table[pos];
		table[pos] = tmp;
	}
private:
	int this_size;
	hashNode<Key, Value>** table;
	
	
};
int main()
{
	unordered_map<int, string>mp(10);
	mp.insert(3, "旧的3");
	mp.insert(5, "旧的5");
	cout << mp[3] << ' ' << mp[5] << endl;
	mp[3] = "新的3";
	cout << mp[3] << ' ' << mp[5] << endl;

}
#endif UNORDEREDMAP

运行结果：