2092-find-all-people-with-secret.adoc

2092. Find All People With Secret

{leetcode}/problems/find-all-people-with-secret/[LeetCode - 2092. Find All People With Secret ^]

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<sub>i</sub>, y<sub>i</sub>, time<sub>i</sub>] indicates that person x<sub>i</sub> and person y<sub>i</sub> have a meeting at time<sub>i</sub>. 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<sub>i</sub> has the secret at time<sub>i</sub>, then they will share the secret with person y<sub>i</sub>, 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:

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.

Example 2:

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.

Example 3:

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.

Constraints:

• 2 ⇐ n ⇐ 105

• 1 ⇐ meetings.length ⇐ 105

• meetings[i].length == 3

• 0 ⇐ x<sub>i</sub>, y<sub>i </sub>⇐ n - 1

• x<sub>i</sub> != y<sub>i</sub>

• 1 ⇐ time<sub>i</sub> ⇐ 105

• 1 ⇐ firstPerson ⇐ n - 1

思路分析

一刷

link:{sourcedir}/_2092_FindAllPeopleWithSecret.java[role=include]

参考资料