Solution Hangover

Link đề bài: http://acm.pku.edu.cn/JudgeOnline/problem?id=1003

Hangover
Time Limit: 1000MS Memory Limit: 10000K
Total Submissions: 59081 Accepted: 27883

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

Source Code
Problem: 1003 User: ductam1983
Memory: 156K Time: 0MS
Language: C Result: Accepted

* Source Code

#include
// #include

#define e 0.00

int main()
{
float n;
float sum;
int i;
while(scanf("%f",&n)&&n!=e)
{
sum=0.00;
i=2;
while(sum {
sum+=(float)1/i++;
// printf("sum=%f i=%d\n",sum,i);getch();
}
printf("%d card(s)\n",i-2);
}
// getch();
return 0;
}