302296: CF442B. Andrey and Problem
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
Creator:
Submit:0
Solved:0
Description
Andrey and Problem
题意翻译
Andrey请教朋友OI题,他知道第$i$个朋友解答出问题题的概率$p_{i}$。 他只想让朋友解答出且仅解答出1道题。 求概率最大。题目描述
Andrey needs one more problem to conduct a programming contest. He has $ n $ friends who are always willing to help. He can ask some of them to come up with a contest problem. Andrey knows one value for each of his fiends — the probability that this friend will come up with a problem if Andrey asks him. Help Andrey choose people to ask. As he needs only one problem, Andrey is going to be really upset if no one comes up with a problem or if he gets more than one problem from his friends. You need to choose such a set of people that maximizes the chances of Andrey not getting upset.输入输出格式
输入格式
The first line contains a single integer $ n $ $ (1<=n<=100) $ — the number of Andrey's friends. The second line contains $ n $ real numbers $ p_{i} $ $ (0.0<=p_{i}<=1.0) $ — the probability that the $ i $ -th friend can come up with a problem. The probabilities are given with at most 6 digits after decimal point.
输出格式
Print a single real number — the probability that Andrey won't get upset at the optimal choice of friends. The answer will be considered valid if it differs from the correct one by at most $ 10^{-9} $ .
输入输出样例
输入样例 #1
4
0.1 0.2 0.3 0.8
输出样例 #1
0.800000000000
输入样例 #2
2
0.1 0.2
输出样例 #2
0.260000000000