hdu 1056

HangOver

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 6772    Accepted Submission(s): 2702

Problem Description

How far can you make a stack of cards overhang a table? If you have one card, you can create a maximum overhang of half a card length. (We're assuming that the cards must be perpendicular to the table.) With two cards you can make the top card overhang the bottom one by half a card length, and the bottom one overhang the table by a third of a card length, for a total maximum overhang of 1/2 + 1/3 = 5/6 card lengths. In general you can make n cards overhang by 1/2 + 1/3 + 1/4 + ... + 1/(n + 1) card lengths, where the top card overhangs the second by 1/2, the second overhangs tha third by 1/3, the third overhangs the fourth by 1/4, etc., and the bottom card overhangs the table by 1/(n + 1). This is illustrated in the figure below.



The input consists of one or more test cases, followed by a line containing the number 0.00 that signals the end of the input. Each test case is a single line containing a positive floating-point number c whose value is at least 0.01 and at most 5.20; c will contain exactly three digits.

For each test case, output the minimum number of cards necessary to achieve an overhang of at least c card lengths. Use the exact output format shown in the examples.

 

Sample Input

  

   1.00
3.71
0.04
5.19
0.00
  

 

Sample Output

  

   3 card(s)
61 card(s)
1 card(s)
273 card(s)
  

 

Source

Mid-Central USA 2001

 

#include <iostream>
using namespace std;
int main()
{
	double n, s;
	int i;
	while(cin>>n)
	{   
		if(n == 0) break;
		i = 0;
		s = 0;
		while(s < n)
		{
			++i;
			s += 1.0 / (i+1);//it must be 1.0, otherwise s is 0 forever.
		}
		cout<<i<<" card(s)"<<endl;
	}
	
	return 0; 
}