Huffuman树 贪心+链表

/*
	贪心算法在于：每次都取数列中最小的两个。

	为什么用链表：方便数组的插入更新，否则还需要每次更新要先找到跟新的位置，再进行数组的移动，很麻烦；

	sort的运用需要掌握，如何从大到小如何从小到大


*/
#include<iostream>
#include<algorithm>
#define MAX 100
using namespace std;
bool compare(int a,int b)
{
	return a>b;
}

typedef struct Link
{
    int value;
    Link *next;
}link,*linkp;

int main()
{
    int i,j;
    linkp hp,np,temp,mp;
	int ans = 0;
    int num;
    int buf[MAX],value_t;
    cin >> num;

    for(i = 0;i < num;i++)
    {
        cin >> buf[i];
    }

    sort(buf,buf + num);
    /*
    for(i = 0;i < num;i++)
    {
        cout << buf[i];
    }
	*/
    hp = np = NULL;


    for(i = 0;i < num;i++)
    {
        if(i == 0)
        {
            hp = np = new link;
            np->value = buf[i];
            np->next = NULL;
        }
        else
        {
            np->next = new link;
            np = np->next;
            np->value = buf[i];
            np->next = NULL;
        }
    }


    //贪心操作

    while(hp->next != NULL)
    {
        temp = hp->next->next;
        mp = hp->next;
        np = temp;
        value_t = hp->value + hp->next->value;
		ans += value_t;
        while(np != NULL && np->value < value_t)
        {
            mp = np;
            np = np->next;
        }

        //插入
        mp->next = new link;
        mp->next->value = value_t;
        mp->next->next = np;
        if(np == temp)//当第三个数大于前两个相加
        {
            temp = mp->next;
        }
        delete hp->next;
        delete hp;
        hp = temp;
    }
	cout << ans;
    system("pause");
    return 0;

}