1942. The Number of the Smallest Unoccupied Chair Medium

1/**
2 * [1942] The Number of the Smallest Unoccupied Chair
3 *
4 * There is a party where n friends numbered from 0 to n - 1 are attending. There is an infinite number of chairs in this party that are numbered from 0 to infinity. When a friend arrives at the party, they sit on the unoccupied chair with the smallest number.
5 * 
6 * 	For example, if chairs 0, 1, and 5 are occupied when a friend comes, they will sit on chair number 2.
7 * 
8 * When a friend leaves the party, their chair becomes unoccupied at the moment they leave. If another friend arrives at that same moment, they can sit in that chair.
9 * You are given a 0-indexed 2D integer array times where times[i] = [arrivali, leavingi], indicating the arrival and leaving times of the i^th friend respectively, and an integer targetFriend. All arrival times are distinct.
10 * Return the chair number that the friend numbered targetFriend will sit on.
11 *  
12 * Example 1:
13 * 
14 * Input: times = [[1,4],[2,3],[4,6]], targetFriend = 1
15 * Output: 1
16 * Explanation: 
17 * - Friend 0 arrives at time 1 and sits on chair 0.
18 * - Friend 1 arrives at time 2 and sits on chair 1.
19 * - Friend 1 leaves at time 3 and chair 1 becomes empty.
20 * - Friend 0 leaves at time 4 and chair 0 becomes empty.
21 * - Friend 2 arrives at time 4 and sits on chair 0.
22 * Since friend 1 sat on chair 1, we return 1.
23 * 
24 * Example 2:
25 * 
26 * Input: times = [[3,10],[1,5],[2,6]], targetFriend = 0
27 * Output: 2
28 * Explanation: 
29 * - Friend 1 arrives at time 1 and sits on chair 0.
30 * - Friend 2 arrives at time 2 and sits on chair 1.
31 * - Friend 0 arrives at time 3 and sits on chair 2.
32 * - Friend 1 leaves at time 5 and chair 0 becomes empty.
33 * - Friend 2 leaves at time 6 and chair 1 becomes empty.
34 * - Friend 0 leaves at time 10 and chair 2 becomes empty.
35 * Since friend 0 sat on chair 2, we return 2.
36 * 
37 *  
38 * Constraints:
39 * 
40 * 	n == times.length
41 * 	2 <= n <= 10^4
42 * 	times[i].length == 2
43 * 	1 <= arrivali < leavingi <= 10^5
44 * 	0 <= targetFriend <= n - 1
45 * 	Each arrivali time is distinct.
46 * 
47 */
48pub struct Solution {}
49
50// problem: https://leetcode.com/problems/the-number-of-the-smallest-unoccupied-chair/
51// discuss: https://leetcode.com/problems/the-number-of-the-smallest-unoccupied-chair/discuss/?currentPage=1&orderBy=most_votes&query=
52
53// submission codes start here
54
55impl Solution {
56    pub fn smallest_chair(times: Vec<Vec<i32>>, target_friend: i32) -> i32 {
57        0
58    }
59}
60
61// submission codes end
62
63#[cfg(test)]
64mod tests {
65    use super::*;
66
67    #[test]
68    fn test_1942() {
69    }
70}
71