第一个使用贪心算法做的ACM题目O(∩_∩)O哈哈~。将兑换比从大到小排序，然后兑换直至完成，输出结果即可

1 #include
      
           2 #include 
       
            3 #include
        
             4 struct Exchange{   5     int room;   6     int javabean;   7 };   8 int cmp( const void *a , const void *b )    9 {   10     struct Exchange *c = (Exchange *)a;   11     struct Exchange *d = (Exchange *)b;   12     if (d->room*1.0/d->javabean > c->room*1.0/c->javabean)  13         return 1;  14     else if (d->room*1.0/d->javabean < c->room*1.0/c->javabean)  15         return -1;  16     else return 0;  17 }   18 double summation(Exchange* ex,int len,int javabeans)  19 {  20     double sum=0;  21     qsort(ex,len,sizeof(Exchange),cmp);  22     for(int i=0;i
         
          0)  25         {  26             sum+=ex[i].room;  27             javabeans-=ex[i].javabean;  28         }  29         else  30         {  31             sum+=javabeans*1.0/ex[i].javabean*ex[i].room;  32             break;  33         }  34     }  35     return sum;  36 }  37 int main()  38 {  39     //freopen("FatNouseTrade.txt","r",stdin);   40     int m,n;  41     while(scanf("%d%d",&m,&n)!=EOF)  42     {  43         if(m==-1&&n==-1)  44             break;  45         Exchange* e=new Exchange[n];  46         for(int i=0;i