CSES - Aalto Competitive Programming 2026 - wk2 - Homework

Submission details
Task:	Connect cities
Sender:	aalto26bh_045
Submission time:	2026-09-03 17:23:17 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	RUNTIME ERROR

Test results
test	verdict	time
#1	RUNTIME ERROR	0.06 s	details
#2	WRONG ANSWER	0.04 s	details
#3	ACCEPTED	0.04 s	details
#4	RUNTIME ERROR	0.06 s	details
#5	ACCEPTED	0.04 s	details
#6	WRONG ANSWER	0.31 s	details
#7	WRONG ANSWER	0.31 s	details
#8	WRONG ANSWER	0.31 s	details
#9	WRONG ANSWER	0.31 s	details
#10	WRONG ANSWER	0.31 s	details
#11	RUNTIME ERROR	0.06 s	details
#12	RUNTIME ERROR	0.06 s	details

Code

def connect_cities():
    x = input()
    n = x.split(" ")[0]
    m = x.split(" ")[1]
    n = int(n)
    m = int(m)

    roads = []
    for _ in range(m):
        x = input()
        roads.append([int(x.split(" ")[0]), int(x.split(" ")[1])])

    buckets = []

    print(f"Roads: ${roads}")
    for idx, road in enumerate(roads):
        a = road[0]
        b = road[1]
        i = 0
        while i < len(buckets):
            bucket = buckets[i]
            if a in bucket:
                j = i + 1
                while j < len(buckets):
                    bucket_2 = buckets[j]
                    if b in bucket_2:
                        bucket[i] = bucket[i].extend(bucket_2)
                        buckets.remove(bucket_2)
                        break
                    j += 1
            elif b in bucket:
                j = i + 1
                while j < len(buckets):
                    bucket_2 = buckets[j]
                    if a in bucket_2:
                        bucket.extend(bucket_2)
                        buckets.remove(bucket_2)
                        break
                    j += 1
            elif idx == len(roads) - 1:
                buckets.append([a, b])

            i += 1
        
        if len(buckets) == 0:
            buckets.append([a, b])


    print(f"Buckets: ${buckets}")

    print(len(buckets) - 1)
    i = 0
    while i < len(buckets) - 2:
        bucket = buckets[i]
        bucket_1 = buckets[i + 1]
        print(f"{bucket[0]} {bucket_1[0]}")
    print(f"{buckets[-2][0]} {buckets[-1][0]}")

    return


if __name__ == "__main__":
    connect_cities()

Test details

Test 1

Verdict: RUNTIME ERROR

input
`10 10 2 5 5 6 1 4 6 8 ...` view save

correct output
`2 1 2 2 7` view save

user output
`Roads: $[[2, 5], [5, 6], [1, 4...` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 63, in <module>
    connect_cities()
  File "/box/input/code.py", line 57, in connect_cities
    print(f"{buckets[-2][0]} {buckets[-1][0]}")
IndexError: list index out of range

Test 2

Verdict: WRONG ANSWER

input
`10 10 3 9 6 8 9 10 7 8 ...` view save

correct output
`2 1 4 4 5` view save

user output
`Roads: $[[3, 9], [6, 8], [9, 1...` view save

Test 3

Verdict: ACCEPTED

input
`10 10 7 9 1 7 1 3 3 4 ...` view save

correct output
`0` view save

user output
`Roads: $[[7, 9], [1, 7], [1, 3...` view save

Test 4

Verdict: RUNTIME ERROR

input
`10 10 4 8 5 9 4 9 2 7 ...` view save

correct output
`1 1 3` view save

user output
`Roads: $[[4, 8], [5, 9], [4, 9...` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 63, in <module>
    connect_cities()
  File "/box/input/code.py", line 57, in connect_cities
    print(f"{buckets[-2][0]} {buckets[-1][0]}")
IndexError: list index out of range

Test 5

Verdict: ACCEPTED

input
`10 10 4 9 2 4 7 10 1 8 ...` view save

correct output
`0` view save

user output
`Roads: $[[4, 9], [2, 4], [7, 1...` view save

Test 6

Verdict: WRONG ANSWER

input
`100000 200000 7233 22146 94937 96203 6133 10731 98737 99193 ...` view save

correct output
`4785 1 2 2 3 3 4 4 5 ...` view save

user output
`Roads: $[[7233, 22146], [94937...` view save

Test 7

Verdict: WRONG ANSWER

input
`100000 200000 92950 93575 24401 88897 41796 99364 47106 50330 ...` view save

correct output
`4868 1 2 2 7 7 9 9 15 ...` view save

user output
`Roads: $[[92950, 93575], [2440...` view save

Test 8

Verdict: WRONG ANSWER

input
`100000 200000 15637 76736 79169 98809 4382 86557 73383 77029 ...` view save

correct output
`4683 1 9 9 20 20 27 27 28 ...` view save

user output
`Roads: $[[15637, 76736], [7916...` view save

Test 9

Verdict: WRONG ANSWER

input
`100000 200000 47932 66981 86401 99942 4353 27841 60492 67345 ...` view save

correct output
`4807 1 6 6 7 7 11 11 12 ...` view save

user output
`Roads: $[[47932, 66981], [8640...` view save

Test 10

Verdict: WRONG ANSWER

input
`100000 200000 6554 44548 76413 98555 5447 59589 70166 74434 ...` view save

correct output
`4786 1 2 2 18 18 21 21 27 ...` view save

user output
`Roads: $[[6554, 44548], [76413...` view save

Test 11

Verdict: RUNTIME ERROR

input
`100000 1 1 2` view save

correct output
`99998 1 3 3 4 4 5 5 6 ...` view save

user output
`Roads: $[[1, 2]] Buckets: $[[1, 2]] 0` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 63, in <module>
    connect_cities()
  File "/box/input/code.py", line 57, in connect_cities
    print(f"{buckets[-2][0]} {buckets[-1][0]}")
IndexError: list index out of range

Test 12

Verdict: RUNTIME ERROR

input
`10 9 2 5 5 6 1 4 6 8 ...` view save

correct output
`2 1 2 2 7` view save

user output
`Roads: $[[2, 5], [5, 6], [1, 4...` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 63, in <module>
    connect_cities()
  File "/box/input/code.py", line 57, in connect_cities
    print(f"{buckets[-2][0]} {buckets[-1][0]}")
IndexError: list index out of range

Aalto Competitive Programming 2026 - wk2 - Homework

Connect cities

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 (aalto26bh_045)