g2001_2100.s2092_find_all_people_with_secret

Class Solution

java.lang.Object

g2001_2100.s2092_find_all_people_with_secret.Solution

public class Solution
extends Object

2092 - Find All People With Secret.

Hard

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.

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 <= xi, yi <= n - 1
• xi != yi
• 1 <= timei <= 105
• 1 <= firstPerson <= n - 1

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
List<Integer>	findAllPeople(int n, int[][] meetings, int firstPerson)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

findAllPeople

public List<Integer> findAllPeople(int n,
                                   int[][] meetings,
                                   int firstPerson)