找出知晓秘密的所有专家

/*
 * Problem: Given n experts, an array of meetings with [xi, yi, timei], and a firstPerson,
 * find all experts who will know the secret after all meetings are done.
 * 
 * Approach:
 * 1. Use a set to keep track of experts who know the secret.
 * 2. Use streams to sort meetings by time and process them.
 * 3. Initialize the set with expert 0 and firstPerson knowing the secret at time 0.
 * 4. For each meeting, if either participant knows the secret, add both to the set.
 * 5. Return the list of experts who know the secret.
 */
import java.util.*;
import java.util.stream.Collectors;

public class SecretSharingStream {
    public List<Integer> findAllExperts(int n, int[][] meetings, int firstPerson) {
        Set<Integer> secretHolders = new HashSet<>();
        secretHolders.add(0);
        secretHolders.add(firstPerson);

        Arrays.stream(meetings)
              .sorted(Comparator.comparingInt(m -> m[2]))
              .forEach(meeting -> {
                  if (secretHolders.contains(meeting[0]) || secretHolders.contains(meeting[1])) {
                      secretHolders.add(meeting[0]);
                      secretHolders.add(meeting[1]);
                  }
              });

        return new ArrayList<>(secretHolders);
    }
}