1227. Airplane Seat Assignment Probability

n passengers board an airplane with exactly n seats. The first passenger has lost the ticket and picks a seat randomly. But after that, the rest of the passengers will: - Take their own seat if it is still available, and - Pick other seats randomly when they find their seat occupied Return the probability that the nth person gets his own seat. Example 1: Input: n = 1 Output: 1.00000 Explana