### restoreArray 
from collections import defaultdict
from typing import *
def f_gold(adjacentPairs: List[List[int]]) -> List[int]:
    graph = defaultdict(list)
    for pair in adjacentPairs:
        graph[pair[0]].append(pair[1])
        graph[pair[1]].append(pair[0])
    ans = []
    vis = set()
    def dfs(idx):
        if idx in vis:
            return
        vis.add(idx)
        ans.append(idx)
        for nxt in graph[idx]:
            dfs(nxt)
    start = -1
    for idx, adj in graph.items():
        if len(adj) == 1:
            start = idx
            break
    dfs(start)
    return ans