今天晚上花了好几个小时写了这个程序。。。都怪我效率太低。。。
好了废话不多说,下面就给出我的代码。(这个代码参考了 严蔚敏老师 的算法)
其中具体的实现就不多讲,因为我在注释都写了。
#include<iostream> using namespace std; struct hTNode{ unsigned int weight; unsigned int parent,lchild,rchild; }; typedef hTNode* huffTree; //定义一个双重指针来存放Huffman编码 typedef char** huffCode; //树上所有结点的个数 int cnt,i; /** * 选择权值最小的两个结点 * tree: 哈弗曼树 * n: 哈弗曼树上结点的个数 * s1,s2: 选出来的结果 ,即在树上的位置 */ void select(huffTree tree, int n, int &s1, int &s2) { int i; for(i = 2; i <= n; i ++) { if(tree[s1].parent != 0) { s1 = i; continue; } if(tree[i].parent == 0) if(tree[i].weight < tree[s1].weight) s1 = i ; } for(i = 1; i <= n; i ++) { if(i == s1) continue; if(s2 == s1 || tree[s2].parent != 0) { s2 = i; continue; } if(tree[i].parent == 0) if(s1 != s2 && tree[i].weight < tree[s2].weight) s2 = i ; } } /** * 这个函数是本程序的最主要的函数,用来建立哈弗曼树,同时生成哈弗曼编码。 * n: 输入的数据的个数 * weight: 每个节点的权值 * tree: 哈弗曼树 * code: 哈弗曼编码 */ void HuffEncoding(int n, int* weight, huffTree &tree, huffCode &codes) { int s1=1, s2=2; huffTree p; //如果输入的数据个数小于2,那么直接返回 if(n < 2) return; cnt = 2*n - 1; //申请这棵哈弗曼树的内存空间 tree = (huffTree)malloc((cnt+1)*sizeof(hTNode)); //把每一个录入的数据建成结点(或者说小树) for(p = tree+1,i = 1; i <= n; ++i, ++p, ++weight) { p->weight = *weight; p->lchild = 0; p->rchild = 0; p->parent = 0; } //初始化哈弗曼树上的每一个结点,先都设成0 for(;i <= cnt; ++i, ++p) { p->weight = 0; p->lchild = 0; p->rchild = 0; p->parent = 0; } //开始建立哈弗曼树 for(i = n + 1; i <= cnt; ++ i) { select(tree, i-1, s1, s2); tree[s1].parent = i; tree[s2].parent = i; tree[i].lchild = s1; tree[i].rchild = s2; tree[i].weight = tree[s1].weight + tree[s2].weight; } //开始求各个叶子结点的Huffman编码 { char* cd; int start,c,f=0; codes = (huffCode)malloc((n+1)*sizeof(char*)); cd = (char*)malloc((n+1)*sizeof(char)); cd[n-1]='\0'; for(i = 1; i <= n; ++i) { start = n - 1; for(c = i,f = tree[i].parent; f != 0; c = f, f = tree[f].parent) if(tree[f].lchild == c) cd[--start] = '0'; else cd[--start] = '1'; codes[i] = (char*)malloc((n - start)*sizeof(char)); strcpy(codes[i],&cd[start]); } free(cd); } }//HuffEncoding int main() { int nn; int* weight; huffTree tree; huffCode codes; cout<<"Please input the count of the number:"; cin>>nn; weight = (int*)malloc(nn*sizeof(int)); cout<<"Input the data one by one:"<<endl; for(i = 0; i < nn; i ++) { cin>>weight[i]; } HuffEncoding(nn,weight,tree,codes); for(i = 1; i <= nn; i ++) { printf("%d:%s\n",tree[i].weight,codes[i]); } return 0; }