POJ

Hangover

Time Limit: 1000MS Memory Limit: 10000K
Total Submissions: 142639 Accepted: 69141
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.

Input

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.

Output

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

数学问题！！！！！！！！！！！！！！！！！！！！

#include<iostream>
#include<cstdio>
using namespace std;
int main()
{
	double sum;
	while (~scanf_s("%lf", &sum), sum)
	{
		double s = 0, a = 0;
		while (sum>s)
		{
			s += 1 / (2 + a);
			a++;
		}
		printf("%.lf card(s)\n", a);
	}
	system("pause");
	return 0;
}

}