Snail’s trouble |
Time Limit: 20000/10000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) |
Total Submission(s): 48 Accepted Submission(s): 32 |
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Problem Description
Once upon a time, there was a poor snail. Every day, it tried
very hard to crawl forward, while there was a keeper who’d like to
maltreat this poor little snail. The snail was crawling on a one-meter
rubber band at first, and it can move on k cm every minute. But after
that, the keeper stretches the rubber band quickly, and it would be
elongated one meter, during that the distances ratio between the snail
and the two endpoints remain unchanged. In the next minute, little snail
tried to keep moving forward again.
“Can I finally get to the endpoint?” The snail often asked himself such a question because he was afraid he would never succeed. Now, we hope you can tell this poor snail when he would reach the endpoint. |
Input
Every line of the input contains an integer number k, indicating
that the snail moved forward k cm every minute. (5 <= k <= 100)
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Output
Output an integer t, indicating that the snail doesn’t get to the
endpoint until t-1 minutes later, while t minutes later, it finally
succeed.
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Sample Input
10 100 |
Sample Output
12367 1 |
思路:看懂题就对了啊。。
另外前几项打一下表,快一点
1 /* 2 Author:wuhuajun 3 */ 4 #include <cmath> 5 #include <cstdio> 6 #include <algorithm> 7 #include <cstring> 8 #include <string> 9 #include <cstdlib> 10 using namespace std; 11 12 typedef long long ll; 13 typedef double dd; 14 const int maxn=210; 15 const dd eps=1E-10; 16 dd sum; 17 int n; 18 19 int dblcmp(dd a) 20 { 21 if (fabs(a)<eps) 22 return 0; 23 if (a>0) 24 return 1; 25 return -1; 26 } 27 28 void close() 29 { 30 exit(0); 31 } 32 33 34 void init() 35 { 36 while (scanf("%d",&n)!=EOF) 37 { 38 if (n==5) 39 { 40 printf("272400600 "); 41 continue; 42 } 43 if (n==6) 44 { 45 printf("9717617 "); 46 continue; 47 } 48 sum=-100; 49 for (int i=1;;i++) 50 { 51 sum+=1.0*n/i; 52 if (dblcmp(sum)>=0) 53 { 54 printf("%d ",i); 55 break; 56 } 57 } 58 } 59 } 60 61 int main () 62 { 63 init(); 64 close(); 65 return 0; 66 }