本文共 2457 字,大约阅读时间需要 8 分钟。
//哈夫曼树构造原则: 权值小的在前,相等的单节点在前;#include "stdafx.h"#include#include #include typedef struct{ unsigned int weight; unsigned int parent,lchild,rchild;}HTNode,*HuffmanTree; typedef char **HuffmanCode;void Select(HuffmanTree &HT, int n, int &s1, int &s2){ //在HT[1..n]中选择parent为0且weight最小的两个结点,// 其序号分别为s1和s2。 int i; s1=-1;s2=-1; for(i=1; i<=n; i++) if(HT[i].parent == 0) { if(s1 == -1) s1 = i; else if(HT[i].weight < HT[s1].weight) { s2 = s1; s1 = i; } else if(s2 == -1 || HT[i].weight < HT[s2].weight) s2 = i; }}void HuffmanCoding(HuffmanTree &HT,HuffmanCode &HC,int *w,int n){ // 并求出n个字符的哈夫曼编码HC int i, m, s1, s2, start; char *cd; unsigned int c, f; if (n<=1) return; m = 2 * n - 1; HT = (HuffmanTree)malloc((m+1) * sizeof(HTNode)); // 0号单元未用 for (i=1; i<=n; i++) { //初始化 HT[i].weight=w[i-1]; HT[i].parent=0; HT[i].lchild=0; HT[i].rchild=0; } for (i=n+1; i<=m; i++) { //初始化 HT[i].weight=0; HT[i].parent=0; HT[i].lchild=0; HT[i].rchild=0; } for (i=n+1; i<=m; i++) { // 建哈夫曼树 // 在HT[1..i-1]中选择parent为0且weight最小的两个结点, // 其序号分别为s1和s2。 Select(HT, i-1, s1, s2); HT[s1].parent = i; HT[s2].parent = i; HT[i].lchild = s1; HT[i].rchild = s2; HT[i].weight = HT[s1].weight + HT[s2].weight; } //--- 从叶子到根逆向求每个字符的哈夫曼编码 --- cd = (char *)malloc(n*sizeof(char)); // 分配求编码的工作空间 cd[n-1] = '\0'; // 编码结束符。 for (i=1; i<=n; ++i) { // 逐个字符求哈夫曼编码 start = n-1; // 编码结束符位置 for (c=i, f=HT[i].parent; f!=0; c=f, f=HT[f].parent) // 从叶子到根逆向求编码 if (HT[f].lchild==c) cd[--start] = '0'; else cd[--start] = '1'; HC[i] = (char *)malloc((n-start)*sizeof(char)); // 为第i个字符编码分配空间 strcpy(HC[i], &cd[start]); // 从cd复制编码(串)到HC } free(cd); //释放工作空间} //HuffmanCodingint _tmain(int argc, _TCHAR* argv[]){ int i,n; int *w; HuffmanTree HT; HuffmanCode HC; printf("Node Number:"); scanf("%d",&n); //权值个数 w=(int *)malloc(n*sizeof(int)); printf("Input weights:"); for ( i=0;i
其中的select()函数亦可如下求解:
int min(HuffmanTree t,int i){ // 函数void select()调用 int j,flag; unsigned int k=UINT_MAX; // 取k为不小于可能的值 for(j=1; j<=i; j++) if(t[j].weights2) { j=s1; s1=s2; s2=j; }*/}
转载地址:http://fdsvi.baihongyu.com/