背包問題課程設計報告
Ⅰ 數據結構課程設計 背包問題 跪求!!!!!
貪心演算法計算:(你可以參考一下下面的代碼)
#include <iostream.h>
struct goodinfo
{
float p; //物品效益
float w; //物品重量
float X; //物品該放的數量
int flag; //物品編號
};//物品信息結構體
void Insertionsort(goodinfo goods[],int n)
{
int j,i;
for(j=2;j<=n;j++)
{
goods[0]=goods[j];
i=j-1;
while (goods[0].p>goods[i].p)
{
goods[i+1]=goods[i];
i--;
}
goods[i+1]=goods[0];
}
}//按物品效益,重量比值做升序排列
void bag(goodinfo goods[],float M,int n)
{
float cu;
int i,j;
for(i=1;i<=n;i++)
goods[i].X=0;
cu=M; //背包剩餘容量
for(i=1;i<n;i++)
{
if(goods[i].w>cu)//當該物品重量大與剩餘容量跳出
break;
goods[i].X=1;
cu=cu-goods[i].w;//確定背包新的剩餘容量
}
if(i<=n)
goods[i].X=cu/goods[i].w;//該物品所要放的量
for(j=2;j<=n;j++)
{
goods[0]=goods[j];
i=j-1;
while (goods[0].flag<goods[i].flag)
{
goods[i+1]=goods[i];
i--;
}
goods[i+1]=goods[0];
}
cout<<"最優解為:"<<endl;
for(i=1;i<=n;i++)
{
cout<<"第"<<i<<"件物品要放:";
cout<<goods[i].X<<endl;
}
}
void main()
{
cout<<"|--------貪心法的解背包問題---------|"<<endl;
int j;
int n;
float M;
goodinfo *goods;//定義一個指針
while(j)
{
cout<<"請輸入物品的總數量:";
cin>>n;
goods=new struct goodinfo [n+1];//
cout<<"請輸入背包的最大容量:";
cin>>M;
cout<<endl;
int i;
for(i=1;i<=n;i++)
{ goods[i].flag=i;
cout<<"請輸入第"<<i<<"件物品的重量:";
cin>>goods[i].w;
cout<<"請輸入第"<<i<<"件物品的效益:";
cin>>goods[i].p;
goods[i].p=goods[i].p/goods[i].w;//得出物品的效益,重量比
cout<<endl;
}
Insertionsort(goods,n);
bag(goods,M,n);
cout<<"press <1> to run agian"<<endl;
cout<<"press <0> to exit"<<endl;
cin>>j;
}
}