程式碼如下：

#include <iostream>
using namespace std;
int s1, s2;

typedef struct {
	int weight;
	int parent, lch, rch;
} HTNode, *HuffmanTree;


void Select(HuffmanTree &HT, int n, int &s1, int &s2) {
	int minv;//定義一個臨時變數儲存最小值
	for (int i = 1; i <= n; i++) { //開始找第一個最小值
		if (HT[i].parent ==
 
 0) {
			minv = i;
			break;
		}
	}
	for (int i = 1; i <= n; i++) {
		if (HT[i].parent == 0)
			if (HT[i].weight < HT[minv].weight)
				minv = i;
	}
	s1 = minv;
	//開始找第二個最小值，且與第一個不同
	for (int i = 1; i <= n; i++) {
		if (HT[i].parent == 0 && i != s1) {
			minv = i;
			break;
		}
	}
	for (
 
int i = 1; i <= n; i++) {
		if (HT[i].parent == 0 && i != s1)
			if (HT[i].weight < HT[minv].weight)
				minv = i;
	}
	s2 = minv;
}


void CreatHuffmanTree(HuffmanTree HT, int n) {
	if (n <= 1)
		return ;
	int m = 2 * n - 1; //陣列共2n-1個元素
	HT = new HTNode[m + 1]; //0號單元未用，HT[m]表示根節點
	for (
 
int i = 1; i <= m; i++) {
		HT[i].lch = 0;//初始化
		HT[i].rch = 0;
		HT[i].parent = 0;
	}
	for (int i = 1; i <= n; i++) {
		cin >> HT[i].weight; //輸入前n個元素的weight值
	}
	//初始化結束，下面開始建立哈夫曼樹

	for (int i = n + 1; i <= m; i++) { //合併產生n-1個結點-構造哈夫曼樹
		Select(HT, i - 1, s1, s2); //在HT[k](1<=k<=i-1)中選擇兩個其雙親域為0,
		//且權重最小的結點，並返回它們在HT中的序號s1和s2
		HT[s1].parent = i;//表示從F中刪除s1,s2
		HT[s2].parent = i;
		HT[i].lch = s1;//s1,s2分別作為i的左右孩子
		HT[i].rch = s2;
		HT[i].weight = HT[s1].weight + HT[s2].weight;//i的權重為左右孩子權重之和
		cout << HT[i].weight << " " << "(" << HT[s1].weight << "," << HT[s2].weight << ")" << endl;
	}
}


int main() {
	HuffmanTree H;
	int n;
	cin >> n;
	CreatHuffmanTree(H, n);
	return 0;
}

測試結果：