CSES - Aalto Competitive Programming 2026 - wk6 - Homework

Submission details
Task:	Course Schedule
Sender:	aalto26fh_050
Submission time:	2026-10-01 13:08:53 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	RUNTIME ERROR

Test results
test	verdict	time
#1	RUNTIME ERROR	0.06 s	details
#2	RUNTIME ERROR	0.06 s	details
#3	RUNTIME ERROR	0.06 s	details
#4	RUNTIME ERROR	0.06 s	details
#5	RUNTIME ERROR	0.06 s	details
#6	RUNTIME ERROR	0.27 s	details
#7	RUNTIME ERROR	0.26 s	details
#8	RUNTIME ERROR	0.27 s	details
#9	RUNTIME ERROR	0.26 s	details
#10	RUNTIME ERROR	0.27 s	details
#11	RUNTIME ERROR	0.21 s	details
#12	RUNTIME ERROR	0.06 s	details
#13	RUNTIME ERROR	0.06 s	details
#14	RUNTIME ERROR	0.23 s	details
#15	RUNTIME ERROR	0.19 s	details
#16	RUNTIME ERROR	0.06 s	details
#17	RUNTIME ERROR	0.21 s	details

Code

from types import GeneratorType


def bootstrap(f, stack=[]):
    def wrapped(*args, **kwargs):
        if stack:
            return f(*args, **kwargs)
        to = f(*args, **kwargs)
        while True:
            if type(to) is GeneratorType:
                stack.append(to)
                to = next(to)
            else:
                stack.pop()
                if not stack:
                    break
                to = stack[-1].send(to)
        return to

    return wrapped


def main():
    n, m = map(int, input().split())
    adj = [[] for _ in range(n + 1)]
    for _ in range(m):
        a, b = map(int, input().split())
        adj[a].append(b)
    status = [0] * (n + 1)
    out = []

    @bootstrap
    def dfs(node: int) -> bool:

        if status[node] == 2:
            return True

        if status[node] == 1:
            return False

        status[node] = 1
        for child in adj[node]:
            if not dfs(child):
                return False

        status[node] = 2
        out.append(node)
        return True

    for i in range(1, n + 1):
        if status[i] == 0:
            if not dfs(i):
                print("IMPOSSIBLE")
                return

    print(" ".join(str(out[i]) for i in range(n - 1, -1, -1)))


main()

Test details

Test 1

Verdict: RUNTIME ERROR

input
`10 20 5 2 2 4 8 9 6 4 ...` view save

correct output
`5 7 10 2 1 8 3 9 6 4` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 2

Verdict: RUNTIME ERROR

input
`10 20 2 7 1 10 9 5 9 7 ...` view save

correct output
`1 8 3 6 10 2 9 4 5 7` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 3

Verdict: RUNTIME ERROR

input
`10 20 8 5 2 3 10 1 9 1 ...` view save

correct output
`4 6 7 9 10 2 8 3 1 5` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 4

Verdict: RUNTIME ERROR

input
`10 20 5 10 10 3 9 10 6 2 ...` view save

correct output
`7 8 6 4 2 1 5 9 10 3` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 5

Verdict: RUNTIME ERROR

input
`10 20 2 9 4 8 9 1 10 6 ...` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 6

Verdict: RUNTIME ERROR

input
`100000 200000 78359 8853 18190 30703 11401 30087 34627 11535 ...` view save

correct output
`2 3 8 9 16 18 21 22 27 34 36 4...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in df...

Test 7

Verdict: RUNTIME ERROR

input
`100000 200000 32395 2098 67067 31866 31867 67167 78488 33397 ...` view save

correct output
`9 11 13 16 22 35 37 38 40 44 5...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 8

Verdict: RUNTIME ERROR

input
`100000 200000 19035 36947 13730 46121 99449 77790 15626 11731 ...` view save

correct output
`1 7 15 17 18 34 38 41 48 49 51...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 9

Verdict: RUNTIME ERROR

input
`100000 200000 14188 9709 46541 20871 32203 88809 99879 54779 ...` view save

correct output
`6 10 11 16 17 19 21 22 23 28 3...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 10

Verdict: RUNTIME ERROR

input
`100000 200000 41882 61162 28138 18053 74649 74863 69760 74508 ...` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in df...

Test 11

Verdict: RUNTIME ERROR

input
`100000 199998 1 100000 1 100000 2 100000 2 100000 ...` view save

correct output
`1 2 3 4 5 6 7 8 9 10 11 12 13 ...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 12

Verdict: RUNTIME ERROR

input
`2 2 1 2 2 1` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 13

Verdict: RUNTIME ERROR

input
`6 6 1 2 2 3 4 3 4 5 ...` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 14

Verdict: RUNTIME ERROR

input
`99999 149997 1 3 3 5 5 7 7 9 ...` view save

correct output
`1 2 3 4 5 6 7 8 9 10 11 12 13 ...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in df...

Test 15

Verdict: RUNTIME ERROR

input
`100000 149998 2 1 3 2 4 3 5 4 ...` view save

correct output
`100000 99999 99998 99997 99996...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 16

Verdict: RUNTIME ERROR

input
`6 6 1 2 1 3 2 4 3 5 ...` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Test 17

Verdict: RUNTIME ERROR

input
`100000 200000 1 1 1 1 2 2 2 2 ...` view save

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 59, in <module>
    main()
  File "/box/input/code.py", line 52, in main
    if not dfs(i):
  File "/box/input/code.py", line 8, in wrapped
    to = f(*args, **kwargs)
  File "/box/input/code.py", line 43, in dfs
    if not dfs(child):
  File "/box/input/code.py", line 14, in wrapped
    stack.pop()
IndexError: pop from empty list

Aalto Competitive Programming 2026 - wk6 - Homework

Course Schedule

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

Test 13

Test 14

Test 15

Test 16

Test 17

Tasks

Submissions (aalto26fh_050)