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#1227
Medium Algorithms

Airplane seat assignment probability

Math Dynamic Programming Brainteaser Probability and Statistics
67.2% acceptance
Feb 25, 2026
658
990
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.

Solution

Rust
Time O(1)
Space O(1)
LeetCode
solution.rs
impl Solution {
  pub fn nth_person_gets_nth_seat(n: i32) -> f64 {
    if n == 1 { 1.0 } else { 0.5 }
  }
}