A Famous Game
http://acm.hdu.edu.cn/showproblem.php?pid=4254
Time Limit: 2000/1000 MS (Java/Others)
Memory Limit: 32768/32768 K (Java/Others)
Problem Description
Mr. B and Mr. M like to play with balls. They have many balls colored in blue and red. Firstly, Mr. B randomly picks up N balls out of them and put them into a bag.
Mr. M knows that there are N+1 possible situations in which the number of red balls is ranged from 0 to N, and we assume the possibilities of the N+1 situations are
the same. But Mr. M does not know which situation occurs. Secondly, Mr. M picks up P balls out of the bag and examines them. There are Q red balls and P-Q blue
balls. The question is: if he picks up one more ball out of the bag, what is the possibility that this ball is red?
Input
Each test case contains only one line with three integers N, P and Q (2 <= N <= 100,000, 0 <= P <= N-1, 0 <= Q <= P).
Output
For each test case, display a single line containing the case number and the possibility of the next ball Mr. M picks out is red. The number should be rounded to four
decimal places.
Sample Input
3 0 0 4 2 1
Sample Output
Hint
Source
Fudan Local Programming Contest 2012
解析见这，但我觉得里面有个公式有点问题。。
完整代码：
/*0ms,260KB*/
#include <cstdio>
int main(void)
{
int T = 0, n, p, q;
while (~scanf("%d%d%d", &n, &p, &q))
printf("Case %d: %.4f\n", ++T, (q + 1.0) / (p + 2));
return 0;
}
