Huffman编码

编码字符："w","o","r","l","d"，权重值4,2,1,5,7。

#include <stdlib.h>
#include <stdio.h>

typedef struct Node{
    int value;
    int parent;
}Node,*HTree;


void printCode(HTree tree,int l,int i);

int main()
{
    int i,j;
    int w[5]={4,2,1,5,7};
    int n = 5;
    HTree tree = (Node*)malloc(sizeof(Node)*(2*n-1));
    //贪心策略构造Huffman树
    for (i=0;i<n;i++)
    {
        tree[i].value = w[i];
        tree[i].parent = 0;
    }
    for (i=n;i<2*n-1;i++)
    {
        int min1 = -1;
        int min2 = -1;
        for (j=0;j<i;j++)
        {
            if (tree[j].parent == 0)
            {
                if (min1 == -1) min1 = j;
                else if (min2 == -1)
                {
                    min2 = j;
                    if (tree[min1].value>tree[min2].value)
                    {
                        int temp = min1;
                        min1 = min2;
                        min2 = temp;
                    }
                }
                else
                {
                    if (tree[j].value<tree[min1].value)
                    {
                        min2 = min1;
                        min1 = j;
                    }
                    else if (tree[j].value<tree[min2].value)
                    {
                        min2 = j;
                    }
                }
            }
        }
        tree[min1].parent = i;
        tree[min2].parent = i;
        tree[i].parent = 0;
        tree[i].value = tree[min1].value+tree[min2].value;
    }

    //递归输出Huffman编码
    for (i=0;i<n;i++)
    {
        printCode(tree,2*n-1,i);
        printf("\r\n");
    }
    return 0;
}

void printCode(HTree tree,int l,int i)
{
    if (tree[i].parent == 0) return;
    printCode(tree,l,tree[i].parent);
    if ((tree[tree[i].parent].value-tree[i].value)>tree[i].value) printf("0");
    else printf("1");
}

 

结果：

01
001
000
10
11