Maximize distance to closest person

/*
 * You are given an array representing a row of seats where seats[i] = 1 represents a person sitting in the ith seat, and seats[i] = 0 represents that the ith seat is empty (0-indexed).
 * There is at least one empty seat, and at least one person sitting.
 * Alex wants to sit in the seat such that the distance between him and the closest person to him is maximized.
 * Return that maximum distance to the closest person.
 * Example 1:
 * Input: seats = [1,0,0,0,1,0,1]
 * Output: 2
 * Explanation:
 * If Alex sits in the second open seat (i.e. seats[2]), then the closest person has distance 2.
 * If Alex sits in any other open seat, the closest person has distance 1.
 * Thus, the maximum distance to the closest person is 2.
 * Example 2:
 * Input: seats = [1,0,0,0]
 * Output: 3
 * Explanation:
 * If Alex sits in the last seat (i.e. seats[3]), the closest person is 3 seats away.
 * This is the maximum distance possible, so the answer is 3.
 * Example 3:
 * Input: seats = [0,1]
 * Output: 1
 * Constraints:
 * 2 <= seats.length <= 2 * 104
 * seats[i] is 0 or 1.
 * At least one seat is empty.
 * At least one seat is occupied.
 */

impl Solution {
  pub fn max_dist_to_closest(seats: Vec<i32>) -> i32 {
    let n = seats.len();
    let mut ans = 0;
    let mut last = -1i32;
    for i in 0..n {
      if seats[i] == 1 {
        if last == -1 {
          // From start to this seat
          ans = ans.max(i as i32);
        } else {
          ans = ans.max((i as i32 - last) / 2);
        }
        last = i as i32;
      }
    }
    // After last seat
    if last != n as i32 - 1 {
      ans = ans.max(n as i32 - 1 - last);
    }
    ans
  }
}