1079 Ratio

校内练习赛做的,数学题,枚举分母

注意要同时计算取上整和下整

1. //4452592_AC_0MS_292K
2. /**********************************************************************
3. *       Online Judge   : POJ
4. *       Problem Title  : Ratio
5. *       ID             : 1079
6. *       Date           : 12/4/2008
7. *       Time           : 14:43:8
8. *       Computer Name  : EVERLASTING-PC
9. ***********************************************************************/
10. #include<iostream>
11. #include<math.h>
12. using namespace std;
14. double n,w,w1,w2;
15. int a,b,zi,deno,d1,d2;
16. bool first;
18. int main()
19. {
20.     //freopen("in_1079.txt","r",stdin);
21.     first=true;
22.     while(cin>>a>>b)
23.     {
24.         if (first)
25.         {
26.             first=false;
27.         }
28.         else
29.         {
30.             cout<<endl;
31.         }
32.         n=(double)a/b;
33.         for(deno=1;deno<=b;++deno)
34.         {
35.             d1=(int)floor(n*(double)deno);
36.             d2=(int)ceil(n*(double)deno);
37.             w1=fabs((double)d1/(double)deno-(double)n);
38.             w2=fabs((double)d2/(double)deno-(double)n);
39.             if(w1<w2)
40.             {
41.                 if(deno==1)
42.                 {
43.                     w=w1;
44.                     cout<<d1<<'/'<<deno<<endl;
45.                 }
46.                 else
47.                 {
48.                     if (w>w1)
49.                     {
50.                         cout<<d1<<'/'<<deno<<endl;
51.                         w=w1;
52.                     }
53.                 }
54.             }
55.             else
56.             {
57.                 if(deno==1)
58.                 {
59.                     w=w2;
60.                     cout<<d2<<'/'<<deno<<endl;
61.                 }
62.                 else
63.                 {
64.                     if (w>w2)
65.                     {
66.                         cout<<d2<<'/'<<deno<<endl;
67.                         w=w2;
68.                     }
69.                 }
70.             }
71.         }
72.     }
73.     return 0;
74. }