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Aalto Competitive Programming 2026 - wk6 - Wed

Fragile network

  • Start: 2026-10-07 16:20:00
  • End: 2026-10-07 17:50:00
Submission details
Task:Fragile network
Sender:aalto26fw_002
Submission time:2026-10-07 17:00:01 +0300
Language:Python3 (PyPy3)
Status:READY
Result:
Test results
testverdicttime
#10.06 sdetails
#2ACCEPTED0.04 sdetails
#30.06 sdetails
#4ACCEPTED0.04 sdetails
#50.06 sdetails
#60.17 sdetails
#7ACCEPTED0.12 sdetails
#80.17 sdetails
#90.14 sdetails
#100.14 sdetails
#11ACCEPTED0.04 sdetails
#120.04 sdetails
#130.04 sdetails
#140.12 sdetails
#150.04 sdetails
#160.04 sdetails
#170.04 sdetails
#180.06 sdetails
#19ACCEPTED0.04 sdetails
#200.06 sdetails
#21ACCEPTED0.04 sdetails

Code

n = int(input())
graph = []
nodes = [0]*(n+1)
for i in range(n-1):
    buffer = input().split()
    a = int(buffer[0])
    b = int(buffer[1])
    nodes[a] += 1
    nodes[b] += 1

res = []
for i in range(1,n+1):
    if nodes[i] == 1:
        res.append(i)

#k = len(res)-1
k = (len(res)+1)//2
print(k)
for j in range(k):
    print(res[2*j],res[2*j+1])

Test details

Test 1

Verdict:

input
10
1 5
1 7
1 8
1 3
...
view save

correct output
5
5 2
7 9
8 6
3 10
...
view save

user output
5
2 3
4 5
6 7
8 9
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 2

Verdict: ACCEPTED

input
10
4 5
3 4
2 3
9 10
...
view save

correct output
1
10 1
view save

user output
1
1 10
view save

Test 3

Verdict:

input
10
1 8
1 3
3 5
5 7
...
view save

correct output
3
7 10
8 2
1 9
view save

user output
3
2 7
8 9
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 4

Verdict: ACCEPTED

input
10
1 5
3 7
2 10
3 8
...
view save

correct output
3
10 8
6 4
5 9
view save

user output
3
4 5
6 8
9 10
view save

Test 5

Verdict:

input
10
4 8
3 4
4 6
2 3
...
view save

correct output
3
8 7
10 9
1 6
view save

user output
3
6 7
8 9
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 6

Verdict:

input
100000
1 56967
1 56618
1 42321
1 82550
...
view save

correct output
50000
56967 16911
56618 39942
42321 99902
82550 2538
...
view save

user output
50000
2 3
4 5
6 7
8 9
...
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 7

Verdict: ACCEPTED

input
100000
92297 92298
23511 23512
68057 68058
65434 65435
...
view save

correct output
1
100000 1
view save

user output
1
1 100000
view save

Test 8

Verdict:

input
100000
17747 97512
10397 12053
679 6975
4013 14565
...
view save

correct output
25057
92881 76094
20353 87429
16069 96487
71186 52809
...
view save

user output
25057
388 577
715 785
837 1166
1220 1261
...
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 9

Verdict:

input
100000
72941 72942
11232 11233
73464 73465
30042 30043
...
view save

correct output
489
16423 85168
20707 94190
36505 54940
96411 44067
...
view save

user output
489
1 99
667 718
884 1400
1404 1453
...
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 10

Verdict:

input
100000
31451 31452
7473 7474
24056 24057
85181 85182
...
view save

correct output
51
25638 2983
87594 87371
92001 50610
46744 100000
...
view save

user output
51
1 140
346 1093
2983 5134
6092 6887
...
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 11

Verdict: ACCEPTED

input
10
1 2
1 3
3 4
3 5
...
view save

correct output
2
2 6
4 10
view save

user output
2
2 4
6 10
view save

Test 12

Verdict:

input
7
1 2
2 3
2 4
1 5
...
view save

correct output
2
4 7
3 6
view save

user output
2
3 4
6 7
view save

Test 13

Verdict:

input
6
1 2
1 3
1 4
4 5
...
view save

correct output
2
3 6
2 5
view save

user output
2
2 3
5 6
view save

Test 14

Verdict:

input
65538
1 2
1 3
1 4
3 5
...
view save

correct output
16385
34 36
40 42
35 41
48 50
...
view save

user output
16385
2 4
33 34
35 36
39 40
...
view save

Test 15

Verdict:

input
11
1 2
1 3
2 4
2 5
...
view save

correct output
2
9 11
8 10
view save

user output
2
8 9
10 11
view save

Test 16

Verdict:

input
7
1 2
1 3
2 4
2 5
...
view save

correct output
2
5 7
4 6
view save

user output
2
4 5
6 7
view save

Test 17

Verdict:

input
7
1 2
1 3
2 4
2 5
...
view save

correct output
2
5 7
4 6
view save

user output
2
4 5
6 7
view save

Test 18

Verdict:

input
10
8 4
3 4
4 6
2 3
...
view save

correct output
3
8 7
10 9
1 6
view save

user output
3
6 7
8 9
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 19

Verdict: ACCEPTED

input
7
1 2
1 5
2 3
2 6
...
view save

correct output
2
6 7
3 4
view save

user output
2
3 4
6 7
view save

Test 20

Verdict:

input
8
1 2
1 3
2 4
2 5
...
view save

correct output
3
4 7
6 8
1 5
view save

user output
3
4 5
6 7
view save

Error:
Traceback (most recent call last):
  File "/box/input/code.py", line 20, in <module>
    print(res[2*j],res[2*j+1])
IndexError: list index out of range

Test 21

Verdict: ACCEPTED

input
10
2 1
3 1
4 2
5 4
...
view save

correct output
3
9 8
6 10
3 7
view save

user output
3
3 6
7 8
9 10
view save

Tasks

A FenceB Microservice hellC Online feudD LaddersE Fragile network

Submissions (aalto26fw_002)

2026-10-07 17:36:18 2026-10-07 17:03:07 2026-10-07 17:00:01 2026-10-07 16:49:53