#2092

Find All People With Secret

candidate master · 1465 · lc hard +32 · verified · 48.4% accepted · 1,943 likes · top 34%

Description

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 holds a secret and shares it with firstPerson at time 0. Whenever a meeting occurs and at least one participant already knows the secret, the other participant learns it too. Sharing happens instantly, so a person who learns the secret at time t can share it with others in meetings also occurring at time t.

Return a list of all people who know the secret once all meetings have concluded. The answer may be returned 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.

Code

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class Solution:
    def findAllPeople(self, n: int, meetings: List[List[int]], firstPerson: int) -> List[int]:

class Solution:
    def findAllPeople(self, n: int, meetings: List[List[int]], firstPerson: int) -> List[int]: