#+ANKI_DECK: study_deck_02 * TODO 2092. Find All People With Secret :hard: :PROPERTIES: :NEETCODE: [[file:../../roadmap.org::*2092. Find All People With Secret][2092. Find All People With Secret]] :END: You are given an integer ~n~ indicating there are ~n~ people numbered from ~0~ to ~n - 1~. You are also given a *0-indexed* 2D integer array ~meetings~ where ~meetings[i] = [x_{i}, y_{i}, time_{i}]~ indicates that person ~x_{i}~ and person ~y_{i}~ have a meeting at ~time_{i}~. A person may attend *multiple meetings* at the same time. Finally, you are given an integer ~firstPerson~. Person ~0~ has a *secret* and initially shares the secret with a person ~firstPerson~ at time ~0~. This secret is then shared every time a meeting takes place with a person that has the secret. More formally, for every meeting, if a person ~x_{i}~ has the secret at ~time_{i}~, then they will share the secret with person ~y_{i}~, and vice versa. The secrets are shared *instantaneously*. That is, a person may receive the secret and share it with people in other meetings within the same time frame. Return /a list of all the people that have the secret after all the meetings have taken place. /You may return the answer in *any order*. *Example 1:* #+begin_src Input: n = 6, meetings = [[1,2,5],[2,3,8],[1,5,10]], firstPerson = 1 Output: [0,1,2,3,5] Explanation: At time 0, person 0 shares the secret with person 1. At time 5, person 1 shares the secret with person 2. At time 8, person 2 shares the secret with person 3. At time 10, person 1 shares the secret with person 5.​​​​ Thus, people 0, 1, 2, 3, and 5 know the secret after all the meetings. #+end_src *Example 2:* #+begin_src Input: n = 4, meetings = [[3,1,3],[1,2,2],[0,3,3]], firstPerson = 3 Output: [0,1,3] Explanation: At time 0, person 0 shares the secret with person 3. At time 2, neither person 1 nor person 2 know the secret. At time 3, person 3 shares the secret with person 0 and person 1. Thus, people 0, 1, and 3 know the secret after all the meetings. #+end_src *Example 3:* #+begin_src Input: n = 5, meetings = [[3,4,2],[1,2,1],[2,3,1]], firstPerson = 1 Output: [0,1,2,3,4] Explanation: At time 0, person 0 shares the secret with person 1. At time 1, person 1 shares the secret with person 2, and person 2 shares the secret with person 3. Note that person 2 can share the secret at the same time as receiving it. At time 2, person 3 shares the secret with person 4. Thus, people 0, 1, 2, 3, and 4 know the secret after all the meetings. #+end_src *Constraints:* - ~2 <= n <= 10^{5}~ - ~1 <= meetings.length <= 10^{5}~ - ~meetings[i].length == 3~ - ~0 <= x_{i}, y_{i }<= n - 1~ - ~x_{i} != y_{i}~ - ~1 <= time_{i} <= 10^{5}~ - ~1 <= firstPerson <= n - 1~ ** TODO Approach Write your approach here. ** TODO Python #+begin_src python class Solution: def findAllPeople(self, n: int, meetings: List[List[int]], firstPerson: int) -> List[int]: #+end_src ** TODO C++ #+begin_src cpp class Solution { public: vector findAllPeople(int n, vector>& meetings, int firstPerson) { } }; #+end_src