哈夫曼樹——離散數學實訓

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
const int maxn = 1e5 + 5;

struct node
{
    int w, pre, l, r;
};
struct tree
{
    int m, root;
    struct node *ht;
};
void print_ans(struct tree *p, int n)
{
    printf("序號 權值 父母 左 右\n");
    for(int i=0;i<2*n-1;i++)
    {
        printf("%d\t%d\t%d\t%d\t%d\n", i, p->ht[i].w, p->ht[i].pre, p->ht[i].l, p->ht[i].r);
    }
}
struct tree *huffman(int n, int *q)
{
    int i, j;
    int m1, m2, x1, x2;
    struct tree *new_node;
    new_node = malloc(sizeof(*new_node));
    new_node->ht = malloc(sizeof(struct node * [2 *n -1]));
    for(i = 0; i<2*n-1; i++)
    {
        new_node->ht[i].l = new_node->ht[i].r = new_node->ht[i].pre = -1;
        if(i < n)
        {
            new_node->ht[i].w = q[i];
        }
        else new_node->ht[i].w = -1;
    }
    printf("初始的狀態：\n");
    print_ans(new_node, n);
    for(i = 0; i<n-1; i++)
    {
        m1 = maxn;
        m2 = maxn;
        x1 = -1;
        x2 = -1;
        for(j = 0; j<n+i;j++)
        {
            if(new_node->ht[j].w < m1 && new_node->ht[j].pre == -1)
            {
                m2 = m1;
                x2 = x1;
                m1 = new_node->ht[j].w;
                x1 = j;
            }
            else if(new_node->ht[j].w < m2 && new_node->ht[j].pre == -1)
            {
                m2 = new_node->ht[j].w;
                x2 = j;
            }
        }
//        printf("小 = %d, 次小 = %d\n", m1, m2);
        new_node->ht[n+i].w = m1 + m2;
        new_node->ht[x1].pre = new_node->ht[x2].pre = new_node->ht[n+i].w;
        new_node->ht[n+i].l = x1;
        new_node->ht[n+i].r = x2;
    }
    new_node->root = 2 * n - 2;
    return new_node;
};
int main()
{
    int i;
    int n;
    int a[maxn];
    struct tree *p;
    while(1)
    {
        printf("請輸入結點數：（輸入0結束）\n");
        scanf("%d", &n);
        if(!n) break;
        printf("輸入%d個節點：\n", n);
        for(int i=0;i<n;i++)
        {
            scanf("%d", &a[i]);
        }
        p = huffman(n, a);
        printf("最優排列方法：\n");
        print_ans(p, n);
    }
    return 0;
}