数据结构实验（9）

PS:仅数据结构实验记录
题目：根据哈夫曼(Huffman)编码的原理，编写一个程序，在用户输入节点权重的基础上建立它的哈夫曼编码。

#include
using namespace std;
const int Max = 10;

struct ElemType
{
	int weight;									//记录权值，假定权值为整数
	int parent, lchild, rchild;							//游标
	char hCode[Max];								//哈夫曼编码
	//string Node;
};

//HuffmanTree类
class HuffmanTree									
{
public:
	HuffmanTree(int w[], int n);						//有参构造函数
	HuffmanTree();								//无参构造函数
	void huffmanTreeCode( int n);					//哈夫曼编码	
	void Print();									//输出路径
	void PrintTreeCode(int n);
private:
	ElemType* huffTree;
	int num;
	void Select(int n, int& i1, int& i2);					//权值最小的根节点下标
};

//选取最小的两个权值下标
void HuffmanTree::Select(int n, int& i1, int& i2)
{
	int i = 0, temp;

	for (; i < n; i++)				//寻找第一个没有双亲的节点，下标赋值给i1
		if (huffTree[i].parent == -1) { i1 = i; break; }
	for (i = i + 1; i < n; i++)			//寻找第二个没有双亲的节点，下标赋值给i2
		if (huffTree[i].parent == -1) { i2 = i; break; }
	if (huffTree[i1].weight > huffTree[i2].weight)//比较i1和i2大小，小的下标赋给i1，大的i2
	{
		temp = i1; i1 = i2; i2 = temp;
	}
	for (i = i + 1; i < n; i++)					//	遍历i后的权值，更新i1和i2
	{
		if (huffTree[i].parent == -1)
		{
//权值小于i1，则i1赋值给i2、i赋值给i1
			if (huffTree[i].weight < huffTree[i1].weight)				{
				i2 = i1; i1 = i;
			}
			else if (huffTree[i].weight < huffTree[i2].weight)	//权值小于i2，i赋值给i2
			{
				i2 = i;
			}
}
}
}

//有参构造函数
HuffmanTree::HuffmanTree(int w[], int n)
{
	int i, k, i1, i2;
	huffTree = new ElemType[2 * n - 1];
	num = n;

	for (i = 0; i < 2 * num - 1; i++)			//初始化，所有结点均没有双亲和孩子
	{
		huffTree[i].parent = -1;
		huffTree[i].lchild = huffTree[i].rchild = -1;
	}

	for (i = 0; i < num; i++)						 //存储叶子结点的权值
		huffTree[i].weight = w[i];

	for (k = num; k < 2 * num - 1; k++)			 //n-1次合并
	{
		Select(k, i1, i2);						 //权值最小的根结点下标为i1和i2
		huffTree[k].weight = huffTree[i1].weight + huffTree[i2].weight;
		huffTree[i1].parent = k; huffTree[i2].parent = k;
		huffTree[k].lchild = i1; huffTree[k].rchild = i2;
	}
}

//确定权值编码
void HuffmanTree::huffmanTreeCode(int n)
{
	char hc[Max];
	int hcLen;
	int i, j, k, parent, p;
	for (i = 0; i < n; i++)
	{
		hcLen = 0;
		parent = huffTree[i].parent;					//待编码字符的双亲结点下标
		p = i;
		while (parent != -1)							//未到达根结点
		{
			if (huffTree[parent].lchild == p)			//左孩子
				hc[hcLen] = '0', hcLen++;

			else if (huffTree[parent].rchild == p)		//右孩子
				hc[hcLen] = '1', hcLen++;

			p = parent;
			parent = huffTree[parent].parent;			//继续向根结点查找
		}
		for (j = 0, k = hcLen - 1; j < hcLen; j++, k--)		//将编码写入相应字符数组
			huffTree[i].hCode[j] = hc[k];
		huffTree[i].hCode[j] = '';					//字符串结束符
	}
	return;
}

//打印权值路径
void HuffmanTree::Print()
{
	int i, k;
	cout << "n每个叶子到根结点的路径是:" << endl;
	for (i = 0; i < num; i++)
	{
		cout << huffTree[i].weight;
		k = huffTree[i].parent;
		while (k != -1)
		{
			cout << "-->" << huffTree[k].weight;
			k = huffTree[k].parent;
		}
		cout << endl;
	}
	cout << "n";
}

//打印权值的哈夫曼编码
void HuffmanTree::PrintTreeCode(int n)
{
	for (int i = 0; i < n; i++)
	{
		int j = 0;
		cout << "权值为： " << huffTree[i].weight << "t哈夫曼编码为: " << huffTree[i].hCode << endl;
	}
}

//测试
int main()
{
	cout << "请输入叶子节点的个数： ";
	int n,j;
	cin >> n;
	int* w = new int[n];
	for (int i = 0; i < n; i++)
	{
		cout << "请输入各叶子节点的权值大小（整数类型）：";
		cin >> j;
		w[i] = j;
	}
	HuffmanTree T{ w, n };
	T.huffmanTreeCode(n);
	T.Print();
	T.PrintTreeCode(n);
	delete[]w;
	return 0;
}

测试结果