哈夫曼树的C语言实现

typedef struct {
	int weight;
	int parent, rchild, lchild;
}HTNode;

void CreatHuffmanTree(int n)  // N leaf nodes.
{
	if (n <= 1) { printf("None."); }
	else 
	{
		int i, weight;
		int m = 2 * n - 1;
		int s1 = 0, s2 = 0;
		HTNode* HT = (HTNode*)malloc(20 * sizeof(HTNode));  // See HT as an array.
		if (HT)
		{
			for (i = 1; i <= m;  i++)  // Initialize the array.
			{
				HT[i].lchild = HT[i].rchild = HT[i].parent = 0;
			}
			for (i = 1; i <= n; i++)
			{
				printf("Input weight:\n");
				scanf_s("%d", &weight);
				HT[i].weight = weight;  // Value assignment.
			}
			for (i = n + 1; i <= m; i++)
			{
				Select(HT, i - 1, m, &s1, &s2);  // Funtion Select chooses the smallest two elements.
				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;
			}
		}
	}	
}

void Select(HTNode* ht, int leaves, int n, int* k1, int* k2)
{
	int i, j = 0, min1 = 19, min2 = 19;
	int p1 = 0, p2 = 0;
	int pos = 0;
	int flag = 0;
	int* num = (int*)malloc(20 * sizeof(int));
	if (num)
	{
		for (i = 1; i <= leaves; i++)
		{
			if (ht[i].parent == 0)
			{
				j++;
				num[j] = ht[i].weight;
			}
		}
		for (i = 1; i <= j; i++)
		{
			if (min1 < num[i] && min1 > 0)
			{
				min1 = min1;
			}
			else
			{
				min1 = num[i];
				pos = i;
			}
		}
		for (i = 1; i <= j; i++)
		{
			if (i != pos && min2 > num[i])
			{
				min2 = num[i];
			}
			else
			{
				min2 = min2;
			}
		}
		for (i = 1; i <= leaves; i++)
		{
			if (flag == 0 && ht[i].weight == min1)
			{
				p1 = i;
				flag = 1;
				continue;
			}
			if (ht[i].weight == min2)
			{
				p2 = i;
				if (flag == 1)
				{
					break;
				}
				else
				{
					continue;
				}
			}
			else
			{
				continue;
			}
		}
		*k1 = p1;
		*k2 = p2;
	}
	else
	{
		printf("ERROR.");
	}
}

int main()
{
	int n = 8;
	CreatHuffmanTree(n);
	return 0;
}