看算法导论补了一下散列表，也就是hash表，hash表还是很好用的，兼顾了空间和时间，查找操作只要O(n/m)，基本的难点在散列函数这里，全域散列这里看不太懂，初步敲了一下除法散列法和乘法散列法的实现，基本没啥好说的，看完开放寻址法以后找两道OJ题做做。

#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
const int hashnum = 7;
const double multipy = (sqrt(5.0) - 1) / 2;

struct hashnode
{
	int data;
	hashnode *next;
};
struct hashlist
{
	int count;
	hashnode *front;
};
hashlist HASH[hashnum];

int HashFunction(int num);
void Initialization();
void HashInsert(int num);
void HashSearch(int num);
void HashPrint();

int main()
{
	int n,num;
	cout << "Enter the total number of what your want to enter" << endl;
	cin >> n;
	int *a = new int[n];
	Initialization();
	for (int i = 0; i < n; i++)
	{
		cin >> a[i];
		HashInsert(a[i]);
	}
	HashPrint();
	cout << "Enter the number you want to search" << endl;
	cin >> num;
	HashSearch(num);
	delete[] a;
	return 0;
}

int HashFunction(int num)//除法散列法or乘法散列法
{
	//return num%hashnum;
	double A = num*multipy - (int)(num*multipy);
	return (int)(hashnum*A);
}
void Initialization()
{
	for (int i = 0; i < hashnum; i++)
	{
		HASH[i].count = 0;
		HASH[i].front = NULL;
	}
}
void HashInsert(int num)
{
	int pos = HashFunction(num);
	hashnode *p = new hashnode;
	HASH[pos].count++;
	p->data = num;
	p->next = HASH[pos].front;
	HASH[pos].front = p;
}
void HashSearch(int num)
{
	int pos = HashFunction(num);
	hashnode *p=HASH[pos].front;
	bool result = false;
	while (p!=NULL)
	{
		if (p->data == num)
		{
			result = true;
			break;
		}
		p = p->next;
	}
	if (result)
		cout << "This number is existed" << endl;
	else
		cout << "The list does not has this number" << endl;
}
void HashPrint()
{
	for (int i = 0; i < hashnum; i++)
	{
		hashnode *p = HASH[i].front;
		cout << "NO "<<i << " has "<<HASH[i].count<<" numbers :";
		while (p!=NULL)
		{
			cout << p->data<<" ";
			p = p->next;
		}
		cout << endl;
	}
}