用贪心算法解决背包问题（物品可分割）

#include"iostream"

#include "vector"

#include<algorithm>

#include <functional>

using namespace std;

 

class Greedy

{

public :

  

   Greedy(int x,vector<int >a,vector<float>b) ;

   void Uint();

   void profit();

private:

    int weight;

       vector<int> storeweight;

       vector<float>everybagprofit;

       vector<float>unitprofit;

};

 

Greedy::Greedy(int x,vector<int >a,vector<float>b)//存放物品重量和价格

{

        weight=x;

              a.swap (storeweight);

              b.swap (everybagprofit);

}

 

void Greedy::Uint()//求解单位重量的价格

{

    float value ;

       for(int i= 0;i<storeweight.size();i++)

       {

             value= everybagprofit[i]/storeweight[i];

             unitprofit.push_back(value);

       }

}

void Greedy::profit()//求解利润

{ 

       float benefit,total=0;

       int   ref=0;

       int  i=0,j=0 ;

   

benefit=*max_element(unitprofit.begin(),unitprofit.end());  //求出单位价值Vcetor中的

//最大值

 

  do

  { 

    for( j ;j<unitprofit.size ()&&weight!=0;)

       {

         if(unitprofit[j]==benefit)

               {

                      ref=j;

             j=i++;

break;

               }

               else

               {

                     j=i++;

                 continue;

               }   

       }//此循环用于找出对应最大利润的物品位置便于找到其重量

    if(storeweight[ref]<weight)//判断重量是否大于背包的重量

       {

              total=unitprofit[ref]*storeweight[ref];

           weight=weight-storeweight[ref];

       }

    else

       { 

        if(weight<=0)

          break;

        else

        {

              total+=unitprofit[ref] * weight;

               weight=weight-storeweight[ref];

        }

       }

               

        remove(unitprofit.begin(),unitprofit.end(),benefit);//移除计算过的最大利润数值       

        i=0;j=0;

 }while(weight!=0);

      

       cout<<"最大收益为"<<total;

}

 

int main()

{

  int Weight,weight,bagsNumber;

  float benefit;

  vector<int>bagsweight ;

  vector<float>bagsprofit ;

 

  cout<<"请输入背包的总重量"<<endl;

  cin>>Weight;

  cout<<endl;

 // Greedy   greedy1(Weight);

 

  cout<<"请输入物品的个数"<<endl;

  cin>>bagsNumber;

cout<<endl;

 

  cout<<"请输入每个物品的重量"<<endl;

   for(int i=0;i<bagsNumber;i++)

   {

        cin>>weight;

        bagsweight.push_back(weight);

   }

   cout<<endl;

 

   cout<<"请输入物品的收益"<<endl;

   for(int j=0;j<bagsNumber;j++)

   {

        cin>>benefit ;

     bagsprofit.push_back(benefit);

   }

   cout<<endl;

  

   Greedy greedy4(Weight,bagsweight,bagsprofit);

   greedy4.Uint();

   greedy4.profit ();

 

 return 0;

}