日期:2014-05-20 浏览次数:21000 次
#include<iostream>
#include<cstdio>
using namespace std;
#include<stdlib.h>
#include<memory.h>
typedef struct
{
int weight;
int flag;
int parent,lchild,rchild;
}Node,*HuffmanTree; //动态分配数组存储赫夫曼树
int L,length;
void Select(HuffmanTree HT, int num, int &s1, int &s2)
{
//s1是最小值,s2是次小值
int i,minx = 1<<30;
int mminx = 1<<30;
for(i = 1; i <= num; ++i)
{
if(HT[i].weight < minx && !HT[i].flag)
{
mminx = minx; s2 = s1;
minx = HT[i].weight; s1 = i;
}
else if(HT[i].weight < mminx && !HT[i].flag)
{
mminx = HT[i].weight; s2 = i;
}
}
HT[s1].flag = HT[s2].flag = -1;
}
void AllLength(HuffmanTree HT, int m)
{
int m1,m2;
length++;
if (!HT[m].lchild && !HT[m].rchild)
{
L += HT[m].weight * (length-1);
}
else
{
m1 = HT[m].lchild;
AllLength(HT,m1);
length--;
m2 = HT[m].rchild;
AllLength(HT,m2);
length--;
}
}
void HuffmanCoding(HuffmanTree &HT,int *w, int n,int m)
{
int i, s1,s2;
//w存放n个字符的权值(均>0),构造赫夫曼树HT
HT = (HuffmanTree)malloc((m+1)*sizeof(Node)); //0号单元未用
HuffmanTree p = HT + 1;
for(i = 1; i <= n; ++i,++p)
{
p->weight = w[i];
p->parent = p->lchild = p->rchild = p->flag = 0;
}
for(i = n+1; i <= m; ++i,++p)
{
p->weight = p->parent = p->lchild = p->rchild = p->flag = 0;
}
for(i = n + 1; i <= m; ++i)
{ //建赫夫曼树
//在HT[1..i-1]选择parent为0且weight最小的两个结点,其序号分别为s1和s2。
Select(HT, i-1, s1, s2);
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;
}
}
int main(void)
{
int i,n,m;
int w[1010];
while(scanf("%d",&n)!=EOF)
{
m = 2 * n - 1;
HuffmanTree T;
for(i = 1; i <= n; ++i)
{
scanf("%d",&w[i]);
}
HuffmanCoding(T,w,n,m);
length = L = 0;
AllLength(T,m);
free(T);
printf("%d\n",L);
}
return 0;
}