Leetcode 2092: Find All People With Secret

In this problem, we are given a set of persons and meetings between people at fixed time, some people know a secret and they are revealing it at each of their meeting. When a person knows a secret, they will reveal it at each of their subsequent meetings. We need to return the set of persons who know the secret at the end of all meetings.

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] = [xi, yi, timei] indicates that person xi and person yi have a meeting at timei. 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 xi has the secret at timei, then they will share the secret with person yi, 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.

A few examples are given as usual:

Some examples for testing