数据结构之 哈希表

头文件：HashTable.h

#define _INT_MIN (0x80000000)
class HashTable
{
public:
	HashTable(int hashLen);
	HashTable(int ary[], int n, int hashLen);
	HashTable(int *start,int *end,int hashLen);
	//获取哈希码
	int HashCode(int key, int *cPtr );
	//冲突处理
	int Collision(int H, int key, int *cPtr );
	//初始化哈希表
	void Initial(int hashLen);

	int ToArray(int ary[]);

	int AddRange(int ary[], int n);

	int Add(int key);
private:
	CirSeqList csl;
	int len;
	
	int SqrtSearchHashes(int H, int key, int *cPtr );
};

void HashTable::Initial(int hashLen)
{
	len = hashLen;
	//初始化 循环表
	int *a = new int[hashLen];
	for (int i = 0; i < hashLen; i++)
	{
		//int的最小值
		a[i] = _INT_MIN;
	}
	csl.Initial(a, hashLen);
	delete[] a;
}

HashTable::HashTable(int hashLen)
{
	Initial(hashLen);
}

HashTable::HashTable(int ary[], int n, int hashLen)
{
	Initial(hashLen);
	AddRange(ary, n);
}

HashTable::HashTable(int *start, int *end, int hashLen)
{
	Initial(hashLen);
	AddRange(start, end - start + 1);
}

int HashTable::Add(int key)
{
	int count = 0, H = HashCode(key, &count);
	if (H != -1)
	{
		csl.Set(H, key);
	}
	else
	{
		//printf("\n*****哈希表溢出！*****\n");
	}
	return count;
}

int HashTable::AddRange(int ary[], int n)
{
	int count = 0;
	for (int i = 0; i < n; i++)
	{
		count+=Add(ary[i]);
	}
	return count;
}

//获取哈希码
int HashTable::HashCode(int key, int *cPtr = NULL)
{
	int H = key%7, count = 1;


	//如果是的，就直接返回。防止重复元素出现。
	if (csl.Get(H) == key)
	{
		return H;
	}
	else if (csl.Get(H) != _INT_MIN)
	{
		//寻找空位
		H = Collision(H, _INT_MIN, &count);
		if (H == -1)
		{
			//printf("\n*****哈希表溢出！*****\n");
			return -1;
		}
	}
	(*cPtr) = count;
	return H;

}
//冲突处理
int HashTable::Collision(int H, int key, int *cPtr = NULL)
{
	bool noway=false;
	int method = 0, tar = -1;

	//遍历处理冲突的方法表
	while (noway == false && method++, tar == -1)
	{
		switch (method)
		{
		case 1:
			//方法一：二次探测再散列
			tar = SqrtSearchHashes(H, key, cPtr);
			break;
		case 2:
			//方法二：。。。。。。
			tar = -1;
			break;
		default:
			//方法表已穷尽
			noway = true;
			break;
		}
	}

	return tar;
}

//1^2 2^2 3^3
int HashTable::SqrtSearchHashes(int H, int key = _INT_MIN, int *cPtr = NULL)
{
	int i = 1, tar = H, d;
	while (csl.IsLegal(tar) && csl.Get(tar) != key)
	{
		if (i > len / 2)
		{
			return -1;
		}
		d = i * i;
		tar = (H + d) % len;
		if (cPtr != NULL)
		{
			(*cPtr)++;
		}
		i++;
	}
	return tar;
}

int HashTable::ToArray(int ary[])
{
	csl.SetCurNum(len-1);
	for (int i = 0; i < len; i++)
	{
		ary[i] = csl.Next();
	}
	return len;
}