Huffman編碼C實現

標籤：編碼   二叉樹   儲存   

Huffman編碼：根據Huffman樹進行編碼的，用到的資料結構是二叉樹。

typedef int elemtype;typedef struct {  elemtype weight;  int parent,l_child,r_child;} binarytree;//2、構建最優二叉樹void CreateHuffman(int leafnum, binarytree *huffmantree){    //leafnum個葉子，決定nodenum個結點數int nodenum=2*leafnum-1;huffmantree=(binarytree *)malloc(nodenum*sizeof(binarytree));   //0號單元也使用//leafnum個葉子，決定nodenum個結點數，也決定了（nodenum-1）個bit位編碼char *huffmancode;huffmancode =(char *)malloc((nodenum-1)*sizeof(char));//huffmantree的初始化:葉子結點data權值手動輸入，非葉子預設值都為0cout<<"請輸入葉子權值：";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從leafnum開始，指的是包含了建立子樹的結點編號for(j=leafnum;j<nodenum;j++){  int w1=32767,w2=0; //儲存最小權值；  int p=0,q=0; //儲存最小權值的編號；      int k;    for(k=0;k<j;k++)  {  if(huffmantree[k].parent==0)  //判斷結點是否使用  {  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對應左節點，編碼為‘0’；q對應左節點，編碼為‘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、尋找從子節點到根節點的編碼 HuffmanCoding(int n,binarytree *HuffmanTree)//針對每一個葉子，從葉子到根方向尋找huffmancode//每一個葉子，對應的編碼長度codelengthconst int maxsize=10;char iscode[maxsize][maxsize];int m;for(m=0;m<leafnum;m++)   //從第一個葉子開始找{      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<<"個葉子的HuffmanCode————";  for(x=0;x<n;x++)   cout<<iscode[m][x];    cout<<endl;} }void main(){   binarytree *T=0;   int leafnum;   printf("輸入葉子數量n=\n");   cin>>leafnum;   CreateHuffman( leafnum, T);   while(1);}

編譯結果如下：