（HDU）1302 -- The Snail（蜗牛）

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cmath>
 4 #include <iostream>
 5 #include <algorithm>
 6 #include <string>
 7 #include <cstdlib>
 8 
 9 using namespace std;
10 
11 int main()
12 {
13     double  height,up,down,factor,delta;
14     while(~scanf("%lf",&height))
15     {
16         if(height==0) break;
17         scanf("%lf %lf %lf",&up,&down,&factor);
18         int day=0,flag=0;
19         double place=0,first=up;
20         delta=(first*factor*0.01);
21         for(day=1;;day++)
22         {
23             if(up>=0) place+=up;
24             if(place>height)
25             {
26                 flag=1;
27                 break;
28             }
29             place-=down;
30             if(place<0)
31             {
32                 flag=0;
33                 break;
34             }
35             if(up>=0) up-=delta;
36         }
37         if(flag) printf("success on day %d\n",day);
38         else printf("failure on day %d\n",day);
39     }
40     return 0;
41 }