CSES - Aalto Competitive Programming 2026 - wk2 - Mon

Submission details
Task:	Building Teams
Sender:	aalto26bm_021
Submission time:	2026-09-07 16:51:05 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	RUNTIME ERROR

Test results
test	verdict	time
#1	RUNTIME ERROR	0.09 s	details
#2	RUNTIME ERROR	0.09 s	details
#3	RUNTIME ERROR	0.09 s	details
#4	RUNTIME ERROR	0.09 s	details
#5	RUNTIME ERROR	0.09 s	details
#6	RUNTIME ERROR	0.26 s	details
#7	RUNTIME ERROR	0.32 s	details
#8	RUNTIME ERROR	0.29 s	details
#9	RUNTIME ERROR	0.36 s	details
#10	RUNTIME ERROR	0.35 s	details
#11	ACCEPTED	0.04 s	details
#12	ACCEPTED	0.04 s	details

Code

n,m = [int(x) for x in input().split()]
mapping = list(range(0,n+1)) #zero ignored
IMPOSSIBLE = False
def sign(a:int): 
    return a//abs(a)
def moreToPopagate(a:int):
    global mapping
    v = mapping[abs(a)]
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
def propagate(a: int):
    global mapping
    global IMPOSSIBLE
    v = mapping[abs(a)]
    if -v == a:
        IMPOSSIBLE = True
    mapping[abs(a)] = mapping[abs(v)]*sign(v)
    if moreToPopagate(a):
        propagate(a)
    
def doMapping(a: int, b:int):
    global mapping
    global IMPOSSIBLE
    if (abs(a) > abs(b)): return doMapping(b,a)
    propagate(a)
    propagate(b)
    if (abs(mapping[abs(a)]) != abs(a) or abs(mapping[b]) != abs(b)): return doMapping(mapping[abs(a)],mapping[abs(b)])
    IMPOSSIBLE = IMPOSSIBLE or (mapping[abs(b)] == a)#*(b//abs(b))
    assert(mapping[abs(a)])
    mapping[abs(b)] = -a

i = m
while i != 0: 
    a,b = input().split()
    doMapping(int(a),int(b))
    i -= 1

for i in range(1,n+1):
    while moreToPopagate(i): 
        propagate(i)
        
if IMPOSSIBLE:
    print("IMPOSSIBLE")
else:
    toPrint = []
    for i in range(1,n+1):
        if mapping[i] < 0: 
            toPrint.append(1)
        else:
            toPrint.append(2)
    print(toPrint)

Test details

Test 1

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1683 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 2

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1683 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 3

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 25, in doMapping
    propagate(b)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1683 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 4

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1683 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 5

Verdict: RUNTIME ERROR

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

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 25, in doMapping
    propagate(b)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1683 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 6

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 25, in doMapping
    propagate(b)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1324 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
  File "/box/input/code.py", line 4, in sign
    def sign(a:int):
RecursionError: maximum recursion depth exceeded

Test 7

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 920 more times]
  File "/box/input/code.py", line 10, in propagate
    def propagate(a: int):
RecursionError: maximum recursion depth exceeded

Test 8

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 25, in doMapping
    propagate(b)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1325 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
RecursionError: maximum recursion depth exceeded

Test 9

Verdict: RUNTIME ERROR

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
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1324 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
RecursionError: maximum recursion depth exceeded

Test 10

Verdict: RUNTIME ERROR

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

correct output
`IMPOSSIBLE` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 34, in <module>
    doMapping(int(a),int(b))
  File "/box/input/code.py", line 24, in doMapping
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  File "/box/input/code.py", line 18, in propagate
    propagate(a)
  [Previous line repeated 1720 more times]
  File "/box/input/code.py", line 17, in propagate
    if moreToPopagate(a):
  File "/box/input/code.py", line 9, in moreToPopagate
    return mapping[abs(a)] != mapping[abs(v)]*sign(v)
RecursionError: maximum recursion depth exceeded

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_021)