CSES - Aalto Competitive Programming 2026 - wk2 - Mon

Submission details
Task:	Building Teams
Sender:	aalto26bm_005
Submission time:	2026-09-07 16:37:52 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	ACCEPTED

Test results
test	verdict	time
#1	ACCEPTED	0.04 s	details
#2	ACCEPTED	0.04 s	details
#3	ACCEPTED	0.04 s	details
#4	ACCEPTED	0.04 s	details
#5	ACCEPTED	0.04 s	details
#6	ACCEPTED	0.36 s	details
#7	ACCEPTED	0.37 s	details
#8	ACCEPTED	0.37 s	details
#9	ACCEPTED	0.37 s	details
#10	ACCEPTED	0.28 s	details
#11	ACCEPTED	0.04 s	details
#12	ACCEPTED	0.04 s	details

Code

n, m = map(int, input().split())

graph = [[] for _ in range(n + 1)]
for _ in range(m):
    a_i, b_i = map(int, input().split())
    graph[a_i].append(b_i)
    graph[b_i].append(a_i)

team = [0] * (n + 1)
for start in range(1, n + 1):
    if team[start] != 0:
        continue

    team[start] = 1
    stack = [start]
    while stack:
        pupil = stack.pop()
        for friend in graph[pupil]:
            if team[friend] == 0:
                team[friend] = 3 - team[pupil]
                stack.append(friend)
            elif team[friend] == team[pupil]:
                print("IMPOSSIBLE")
                exit()

print(*team[1:])

Test details

Test 1

Verdict: ACCEPTED

input
`10 20 3 4 8 10 3 7 1 8 ...` view save

correct output
`1 1 1 2 2 1 2 2 2 1` view save

user output
`1 1 1 2 2 1 2 2 2 1` view save

Test 2

Verdict: ACCEPTED

input
`10 20 1 3 8 10 2 4 6 8 ...` view save

correct output
`1 1 2 2 1 1 1 2 1 1` view save

user output
`1 1 2 2 1 1 1 2 1 1` view save

Test 3

Verdict: ACCEPTED

input
`10 20 7 10 3 10 9 10 2 10 ...` view save

correct output
`1 2 2 1 1 1 2 1 2 1` view save

user output
`1 2 2 1 1 1 2 1 2 1` view save

Test 4

Verdict: ACCEPTED

input
`10 20 2 4 2 10 7 10 4 6 ...` view save

correct output
`1 2 1 1 2 2 2 1 2 1` view save

user output
`1 2 1 1 2 2 2 1 2 1` view save

Test 5

Verdict: ACCEPTED

input
`10 20 3 5 8 10 9 10 1 8 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 6

Verdict: ACCEPTED

input
`100000 200000 47355 96505 90709 92058 735 80715 91802 94265 ...` view save

correct output
`1 2 2 1 2 1 1 1 2 2 1 2 1 1 1 ...` view save

user output
`1 2 2 1 2 1 1 1 2 2 1 2 1 1 1 ...` view save

Test 7

Verdict: ACCEPTED

input
`100000 200000 59991 95794 95150 96051 78453 94730 90411 95523 ...` view save

correct output
`1 1 1 2 2 1 1 2 1 2 1 2 2 2 1 ...` view save

user output
`1 1 1 2 2 1 1 2 1 2 1 2 2 2 1 ...` view save

Test 8

Verdict: ACCEPTED

input
`100000 200000 89827 96402 65137 86792 80965 94708 19479 48078 ...` view save

correct output
`1 2 1 1 2 1 2 2 2 1 2 1 1 2 1 ...` view save

user output
`1 2 1 1 2 1 2 2 2 1 2 1 1 2 1 ...` view save

Test 9

Verdict: ACCEPTED

input
`100000 200000 72952 83723 66197 70052 2949 52160 55753 95651 ...` view save

correct output
`1 1 2 2 2 1 1 2 2 2 2 2 1 2 1 ...` view save

user output
`1 1 2 2 2 1 1 2 2 2 2 2 1 2 1 ...` view save

Test 10

Verdict: ACCEPTED

input
`100000 200000 38942 96755 70049 82663 7746 72732 87819 99029 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 11

Verdict: ACCEPTED

input
`5 4 1 2 3 4 4 5 5 3` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 12

Verdict: ACCEPTED

input
`4 5 1 2 1 4 2 3 2 4 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Aalto Competitive Programming 2026 - wk2 - Mon

Building Teams

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Tasks

Submissions (aalto26bm_005)