Building Teams

from collections import defaultdict, deque

n, m = [int(x) for x in input().split()]
graph = defaultdict(list)
for i in range(m):
    a, b = [int(x)-1 for x in input().split()]
    graph[a].append(b)
    graph[b].append(a)

teams = [0 for i in range(n)]

def bipartite():
    for i in range(n):
        if teams[i] == 0:
            teams[i] = 1
            queue = deque([i])

            while queue:
                node = queue.popleft()
                for neighbor in graph[node]:
                    if teams[neighbor] == 0:
                        teams[neighbor] = 3 - teams[node]
                        queue.append(neighbor)
                    elif teams[neighbor] == teams[node]:
                        return False
    return True

result = bipartite()

if result:
    for i in teams:
        print(i, end=' ')
else:
    print("IMPOSSIBLE")

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED