#include <unordered_map>
#include <iostream>
#include <string>
using namespace std;

class hashdef{
public:
	//template<class T>，不太好分类型，就直接用string了 
	size_t operator()(const string& a) const{//这里必须有const，在hash内部会把其当const调用 
	//同样不能有static，调用需要用到this 
		int hash;
		int seed = 114514;
		for(char x : a){	
			hash += static_cast<int>(x)*31 + seed;
			hash %= 1009;
		}
		return hash;
	}
};
int main(){
	hashdef a;
	unordered_map<string, string, hashdef> m1{make_pair("1","111")};
	unordered_map<string, string> m2;
	m1.insert({make_pair("2","222"),make_pair("3","333"),make_pair("6","666"),make_pair("5","555")});
	//下面首先查看哈希值
	cout << a("1") << " " << a("2") << " " << a("3") << " " << a("5") << " " << a("6") << endl;
	m1.rehash(1000);//重新设置桶的个数为1009，配合hash(此时会重新计算所有hash)
	m2.max_load_factor(0.7f);//重新设置-控制扩容-负载因子=元素个数/桶个数，这里是平均每个桶最多0.7个元素
	cout << "bucket_count: " << m1.bucket_count() << endl;//hashtable_policy.h中的质数表跳转到最近的大于n的数 
	cout << m1.max_load_factor() << " " << m1.load_factor() << endl;
	m1["7"] = "777";
	cout << m1.at("6") << " " << m1["5"] << " " << m1.find("6")->second << endl;
	return 0;
}
/*
1007 29 60 122 153
bucket_count: 1031
1 0.00484966
666 555 666
*/