HDOJ 1009 FatMouse' Trade

　　　　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

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 1 #include<stdio.h>   
 2 #include <memory.h>   
 3 #include<stdlib.h>   
 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<len;i++)  
23     {  
24         if(javabeans-ex[i].javabean>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<n;i++)  
47             scanf("%d%d",&(e[i].room),&(e[i].javabean));  
48         double result=summation(e,n,m);  
49         printf("%.3lf\n",result);  
50     }  
51     return 0;  
52 }



posted on 2011-07-31 21:16  AdaByron  阅读(229)  评论(0)    收藏  举报

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