### findAllPeople 
from collections import deque
from collections import defaultdict
from typing import *
def f_gold(n: int, meetings: List[List[int]], firstPerson: int
) -> List[int]:
    vis = [False] * n
    vis[0] = vis[firstPerson] = True
    meetings.sort(key=lambda x: x[2])
    i, m = 0, len(meetings)
    while i < m:
        j = i
        while j + 1 < m and meetings[j + 1][2] == meetings[i][2]:
            j += 1
        s = set()
        g = defaultdict(list)
        for x, y, _ in meetings[i : j + 1]:
            g[x].append(y)
            g[y].append(x)
            s.update([x, y])
        q = deque([u for u in s if vis[u]])
        while q:
            u = q.popleft()
            for v in g[u]:
                if not vis[v]:
                    vis[v] = True
                    q.append(v)
        i = j + 1
    return [i for i, v in enumerate(vis) if v]