Huffman编码C实现

Huffman编码：根据Huffman树进行编码的，用到的数据结构是二叉树。

typedef int elemtype;
typedef struct
{
  elemtype weight;
  int parent,l_child,r_child;
} binarytree;

//2、构建最优二叉树
void CreateHuffman(int leafnum, binarytree *huffmantree)
{
    //leafnum个叶子，决定nodenum个结点数
	int nodenum=2*leafnum-1;
	huffmantree=(binarytree *)malloc(nodenum*sizeof(binarytree));   //0号单元也使用

	//leafnum个叶子，决定nodenum个结点数，也决定了（nodenum-1）个bit位编码
	char *huffmancode;
	huffmancode =(char *)malloc((nodenum-1)*sizeof(char));

	//huffmantree的初始化:叶子结点data权值手动输入，非叶子默认值都为0
	cout<<"请输入叶子权值：";
	int i;
	for(i=0;i<nodenum;i++)
	{
		if(i<leafnum)
		{
			cin>>huffmantree[i].weight;
		}
		else
		{
		   huffmantree[i].weight=0;
		}
		huffmantree[i].parent=huffmantree[i].l_child=huffmantree[i].r_child=0;
	}

	int j;
	//j从leafnum开始，指的是包含了新建子树的结点编号
	for(j=leafnum;j<nodenum;j++)
	{
	  int w1=32767,w2=0; //存储最小权值；
	  int p=0,q=0; //存储最小权值的编号；

	      int k;
		  for(k=0;k<j;k++)
			  {
				  if(huffmantree[k].parent==0)  //判断结点是否使用
				  {
					  if(huffmantree[k].weight<w1)
						  {
						   w2=w1;
						   q=p;
						   w1=huffmantree[k].weight;
						   p=k;					   

						  }
					  else if(huffmantree[k].weight<w2)
						 {
						   w2=huffmantree[k].weight;
						   q=k;
						 }
				  }
			   }
		//p对应左节点，编码为‘0’；q对应左节点，编码为‘1’；
		huffmancode[p]='0';
		huffmancode[q]='1';

		huffmantree[j].weight =w1+w2;
		huffmantree[j].l_child=p;
		huffmantree[j].r_child=q;
		huffmantree[p].parent=j;
		huffmantree[q].parent=j;
	}

//3、寻找从子节点到根节点的编码 HuffmanCoding(int n,binarytree *HuffmanTree)
	//针对每一个叶子，从叶子到根方向寻找huffmancode
	//每一个叶子，对应的编码长度codelength
	const int maxsize=10;
	char iscode[maxsize][maxsize];
	int m;
	for(m=0;m<leafnum;m++)   //从第一个叶子开始找
	{
      int n=0;
	  iscode[m][n]=huffmancode[m];
	  int parent=huffmantree[m].parent;
	  while(parent !=0)
		{
		  iscode[m][++n]=huffmancode[parent];
		  parent=huffmantree[parent].parent;
		};

	  int x;
	  cout<<"第"<<m+1<<"个叶子的HuffmanCode————";
	  for(x=0;x<n;x++)
	   cout<<iscode[m][x];
	  cout<<endl;
	}
}

void main()
{
   binarytree *T=0;
   int leafnum;
   printf("输入叶子数量n=\n");
   cin>>leafnum;
   CreateHuffman( leafnum, T);
   while(1);
}

编译结果如下：

Huffman编码C实现