Solution to https://open.kattis.com/problems/wheresmyinternet

wheresmyinternet.py

#!/usr/bin/env python3
import sys
from collections import defaultdict

line =  sys.stdin.readline()
n = int(line.split(' ')[0])
d = defaultdict(list)
for line in sys.stdin.readlines():
    src, dst = [int(x) for x in line.split(' ')]
    d[src].append(dst)
    d[dst].append(src)

unvisited = set(range(1, n + 1))
q = [1]
while q:
    r = []
    for a in q:
        unvisited.discard(a)
        for neighbor in d[a]:
            if neighbor in unvisited:
                r.append(neighbor)
    q = r

if not unvisited:
    print("Connected")
else:
    for x in sorted(unvisited):
        print(x)