#K63327. Ticket Vending Machine Problem
Ticket Vending Machine Problem
Ticket Vending Machine Problem
You are given several ticket vending machines, each with its own probability of dispensing a ticket. Your task is to determine the expected number of passengers required to obtain one ticket from the machine with the highest probability.
Mathematically, if a machine has a probability \(p\) of dispensing a ticket, then the expected number of passengers needed is given by
[ E = \frac{1}{p_{\max}} ]
where \(p_{\max}\) is the maximum probability among the given probabilities. If \(p_{\max} = 0\), then the result is considered to be infinity.
The answer should be printed with 6 decimal places.
inputFormat
The first line of the input contains an integer \(T\) denoting the number of test cases. Each test case consists of two lines:
- The first line contains an integer \(n\) denoting the number of machines.
- The second line contains \(n\) space-separated floating-point numbers denoting the probabilities for each machine.
All input is read from standard input (stdin).
outputFormat
For each test case, output a single line containing the expected number of passengers required to obtain one ticket from the machine with the highest probability, formatted to 6 decimal places. All output should be written to standard output (stdout).
## sample3
3
0.2 0.5 0.8
2
0.1 0.9
4
0.3 0.4 0.6 0.9
1.250000
1.111111
1.111111
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