public class Solution
extends Object
1227 - Airplane Seat Assignment Probability\.
Medium
`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
**Explanation:** The first person can only get the first seat.
**Example 2:**
**Input:** n = 2
**Output:** 0.50000
**Explanation:** The second person has a probability of 0.5 to get the second seat (when first person gets the first seat).
**Constraints:**
* 1 <= n <= 105