构造哈夫曼树

缺点：在找最小值和次小次时，会比已经匹配过的点再重新比较一次，有点浪费。 以后算法学好了再回来看看有什么可以更好的实现方法吧

#include "stdafx.h"
#define N 10					//结点个数
#define MAXVALUE 1000000		//作比较用
typedef struct {
	int weight;			//权值
	int parent;
	int lchild;
	int rchild;
}HaffmanType;

int main()
{
	HaffmanType hfmanTree[2*N-1]; //因为要多一个结点来连接其它结点
	for (int i = 0; i <2 * N - 1; i++)
	{
		hfmanTree[i].weight = -1;
		hfmanTree[i].parent = -1;
		hfmanTree[i].lchild = -1;
		hfmanTree[i].rchild = -1;
	}
	hfmanTree[0].weight = 2;
	hfmanTree[2].weight = 5;
	hfmanTree[1].weight = 3;
	hfmanTree[3].weight = 1;
	hfmanTree[5].weight = 8;
	hfmanTree[7].weight = 2;
	hfmanTree[8].weight = 12;
	hfmanTree[9].weight = 52;
	hfmanTree[10].weight = 10;
	hfmanTree[11].weight = 9;
	int x1, x2,m1,m2;		//x1是用来选最小值，x2用来选次小值,m1用来保留最小值的下标，m2用来保留次小值下标
	for (int i = 0; i < N-1; i++)
	{
		x1 = x2 = MAXVALUE;
		m1 = m2 = 0;

		for (int j = 0; j < N+i; j++)
		{
			if (hfmanTree[j].parent==-1&&hfmanTree[j].weight<x1)
			{
				x2 = x1;
				m2 = m1;
				x1 = hfmanTree[j].weight;
				m1 = j;
			}
			else if(hfmanTree[j].parent == -1 && hfmanTree[j].weight<x2)
			{
				x2 = hfmanTree[i].weight;
				m2 = j;
			}
		}
		hfmanTree[m1].parent = N + i;
		hfmanTree[m2].parent = N + i;
		hfmanTree[N + i].weight = hfmanTree[m1].weight + hfmanTree[m2].weight;
		hfmanTree[N + i].lchild = m1;
		hfmanTree[N + i].rchild = m2;

	}

    return 0;
}