【数据结构】哈夫曼树（10）

struct HTNode
{
    int weight;
    int parent;
    int left_child;
    int right_child;
};

void select_Min(struct HTNode * HT ,int length, int * e1, int * e2)
{
    int min1, min2;
    min1 = min2 = INT_MAX;
    int pos1, pos2;
    pos1 = pos2 = 0;
    for(int i = 1; i < length + 1; ++i)
    {
        if (HT[i].parent == 0)
        {
            //!parent==0说明在森林中
            if(HT[i].weight < min1)
            {
                min2 = min1;
                pos2 = pos1;
                min1 = HT[i].weight;
                pos1 = i;
            }
            else if (HT[i].weight < min2)
            {
                min2 = HT[i].weight;
                pos2 = i;
            }
        }
    }
    *e1 = pos1;
    *e2 = pos2;
}
//构造哈夫曼树
void createHuffmanTree(struct HTNode ** HT, int n)
{
    //1初始化
    if (n <= 1)
        return;
    int m = 2 * n - 1;
    *HT = (struct HTNode *) malloc(sizeof (struct HTNode) * (m + 1));
    for (int i = 1; i <= m; i++)
    {
        (*HT)[i].left_child = 0;
        (*HT)[i].right_child = 0;
        (*HT)[i].parent = 0;
    }
    for (int i = 1; i <= n; i++)
    {
        printf("输入第 %d 个结点的权重：", i);
        fflush(stdout);
        scanf("%d", &(*HT)[i].weight);
    }
    //2建立哈夫曼树
    int s1, s2;
    for (int i = n+1; i <= m; i++)
    {
        select_Min(*HT, i - 1, &s1, &s2);
        (*HT)[s1].parent = i;
        (*HT)[s2].parent = i;
        (*HT)[i].left_child = s1;
        (*HT)[i].right_child = s2;
        (*HT)[i].weight = (*HT)[s1].weight + (*HT)[s2].weight;
    }

}

void huffmanCoding(struct HTNode ** HT, char *** HC, int n)
{
    int start;
    int f;
    int c;
    char * cd;
    *HC = (char **) malloc(sizeof (char *) * (n + 1));
    cd = (char *) malloc(sizeof (char) * n);
    cd[n-1] = '';

    for (int i = 0; i <= n; ++i)
    {
        start = n - 1;
        c = i;
        f = (*HT)[i].parent;
        while (f != 0)
        {
            if ((*HT)[f].left_child == c)
                cd[--start] = '0';
            else
                cd[--start] = '1';
            c = f;
            f = ((*HT)[f].parent);
        }
        (*HC)[i] = (char *) malloc(sizeof (char ) * (n - start));
        strcpy((*HC)[i], &cd[start]);
    }
    free(cd);
}

#include 
#include 
#include 
#include 
#define NODES 8

int main()
{
    struct HTNode * T;
    char ** HC;
    createHuffmanTree(&T, NODES);
    for(int i = 1; i < 2 * NODES; ++i)
    {
        printf("%dtweight = %dtparent = %dtleft_child=%dtright_child=%dn",
               i, T[i].weight, T[i].parent, T[i].left_child, T[i].right_child);
    }
    huffmanCoding(&T, &HC, 8);
    int a = 65;
    for (int i = 1; i <= NODES; i++)
    {
        printf("%c = %sn", a, HC[i]);
        a++;
    }
    return 0;
}