CSES - Aalto Competitive Programming 2026 - wk5 - Mon

Submission details
Task:	Freight trains
Sender:	aalto26em_005
Submission time:	2026-09-28 17:46:33 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	RUNTIME ERROR

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	0.04 s	details
#7	ACCEPTED	0.04 s	details
#8	ACCEPTED	0.04 s	details
#9	ACCEPTED	0.04 s	details
#10	ACCEPTED	0.04 s	details
#11	ACCEPTED	0.04 s	details
#12	ACCEPTED	0.04 s	details
#13	ACCEPTED	0.04 s	details
#14	ACCEPTED	0.04 s	details
#15	ACCEPTED	0.04 s	details
#16	ACCEPTED	0.04 s	details
#17	ACCEPTED	0.04 s	details
#18	ACCEPTED	0.04 s	details
#19	RUNTIME ERROR	0.06 s	details
#20	ACCEPTED	0.04 s	details
#21	RUNTIME ERROR	0.06 s	details
#22	ACCEPTED	0.04 s	details
#23	ACCEPTED	0.04 s	details
#24	ACCEPTED	0.04 s	details
#25	ACCEPTED	0.04 s	details
#26	ACCEPTED	0.04 s	details
#27	ACCEPTED	0.04 s	details
#28	ACCEPTED	0.04 s	details
#29	RUNTIME ERROR	0.06 s	details
#30	ACCEPTED	0.04 s	details
#31	RUNTIME ERROR	0.06 s	details
#32	RUNTIME ERROR	0.06 s	details
#33	RUNTIME ERROR	0.06 s	details
#34	RUNTIME ERROR	0.06 s	details
#35	RUNTIME ERROR	0.06 s	details
#36	ACCEPTED	0.04 s	details
#37	RUNTIME ERROR	0.06 s	details
#38	ACCEPTED	0.04 s	details
#39	RUNTIME ERROR	0.06 s	details
#40	RUNTIME ERROR	0.06 s	details
#41	RUNTIME ERROR	0.06 s	details
#42	RUNTIME ERROR	0.07 s	details
#43	RUNTIME ERROR	0.07 s	details
#44	RUNTIME ERROR	0.06 s	details
#45	RUNTIME ERROR	0.06 s	details
#46	RUNTIME ERROR	0.06 s	details
#47	RUNTIME ERROR	0.07 s	details
#48	RUNTIME ERROR	0.07 s	details
#49	RUNTIME ERROR	0.06 s	details
#50	RUNTIME ERROR	0.06 s	details
#51	RUNTIME ERROR	0.06 s	details
#52	RUNTIME ERROR	0.07 s	details
#53	RUNTIME ERROR	0.07 s	details
#54	RUNTIME ERROR	0.07 s	details
#55	RUNTIME ERROR	0.07 s	details
#56	RUNTIME ERROR	0.07 s	details
#57	RUNTIME ERROR	0.07 s	details
#58	RUNTIME ERROR	0.07 s	details
#59	RUNTIME ERROR	0.07 s	details
#60	RUNTIME ERROR	0.07 s	details
#61	RUNTIME ERROR	0.07 s	details
#62	RUNTIME ERROR	0.14 s	details
#63	RUNTIME ERROR	0.14 s	details
#64	RUNTIME ERROR	0.14 s	details
#65	RUNTIME ERROR	0.13 s	details
#66	RUNTIME ERROR	0.13 s	details
#67	RUNTIME ERROR	0.14 s	details
#68	RUNTIME ERROR	0.13 s	details
#69	RUNTIME ERROR	0.14 s	details
#70	RUNTIME ERROR	0.13 s	details
#71	RUNTIME ERROR	0.14 s	details

Code

n = int(input())
ids = []
for _ in range(n):
    ids.append(input())
ids.sort()

def compare(j=0):
    if j >= len(ids)-1:
        return ids.pop()
    s1 = ids[j]
    s2 = ids[j+1]
    if s1[0] == s2[len(s1)]:
        return compare(j+1)
    elif s1[0] < s2[len(s1)]:
        return ids.pop(j)
    else:
        return ids.pop(j+1)
    
res = ""
while (len(ids) > 1):
    s1 = ids[0]
    s2 = ids[1]
    if len(s1) != len(s2) and s2[:len(s1)]==s1:    
        res += compare()
    else:
        res += s1
        ids.pop(0)
        continue
res += ids.pop()
print(res)

Test details

Test 1

Verdict: ACCEPTED

input
`1 gl` view save

correct output
`gl` view save

user output
`gl` view save

Test 2

Verdict: ACCEPTED

input
`2 adedf ff` view save

correct output
`adedfff` view save

user output
`adedfff` view save

Test 3

Verdict: ACCEPTED

input
`2 jb lj` view save

correct output
`jblj` view save

user output
`jblj` view save

Test 4

Verdict: ACCEPTED

input
`2 qlipb sr` view save

correct output
`qlipbsr` view save

user output
`qlipbsr` view save

Test 5

Verdict: ACCEPTED

input
`3 f llk onfj` view save

correct output
`fllkonfj` view save

user output
`fllkonfj` view save

Test 6

Verdict: ACCEPTED

input
`3 jaeo mob nk` view save

correct output
`jaeomobnk` view save

user output
`jaeomobnk` view save

Test 7

Verdict: ACCEPTED

input
`3 nemlo psqhy sg` view save

correct output
`nemlopsqhysg` view save

user output
`nemlopsqhysg` view save

Test 8

Verdict: ACCEPTED

input
`4 dia eh fbcae gf` view save

correct output
`diaehfbcaegf` view save

user output
`diaehfbcaegf` view save

Test 9

Verdict: ACCEPTED

input
`4 c cbfaa egbg fc` view save

correct output
`cbfaacegbgfc` view save

user output
`cbfaacegbgfc` view save

Test 10

Verdict: ACCEPTED

input
`4 cbc cdd ceed dbeea` view save

correct output
`cbccddceeddbeea` view save

user output
`cbccddceeddbeea` view save

Test 11

Verdict: ACCEPTED

input
`4 bfec bgbaf fcg fdbbg` view save

correct output
`bfecbgbaffcgfdbbg` view save

user output
`bfecbgbaffcgfdbbg` view save

Test 12

Verdict: ACCEPTED

input
`5 aoefh ge imgjj kmj ...` view save

correct output
`aoefhgeimgjjkmjmhhi` view save

user output
`aoefhgeimgjjkmjmhhi` view save

Test 13

Verdict: ACCEPTED

input
`5 bcbec ei fdigc ilabd ...` view save

correct output
`bcbeceifdigcilabdlg` view save

user output
`bcbeceifdigcilabdlg` view save

Test 14

Verdict: ACCEPTED

input
`5 a d db glfff ...` view save

correct output
`adbdglfffih` view save

user output
`adbdglfffih` view save

Test 15

Verdict: ACCEPTED

input
`5 ab d ebhin k ...` view save

correct output
`abdebhinknab` view save

user output
`abdebhinknab` view save

Test 16

Verdict: ACCEPTED

input
`5 fasgx o oezws qua ...` view save

correct output
`fasgxoezwsoquaspfd` view save

user output
`fasgxoezwsoquaspfd` view save

Test 17

Verdict: ACCEPTED

input
`5 bcggd dcg e fc ...` view save

correct output
`bcggddcgefcg` view save

user output
`bcggddcgefcg` view save

Test 18

Verdict: ACCEPTED

input
`5 cmo cx hftbb mil ...` view save

correct output
`cmocxhftbbmiltksr` view save

user output
`cmocxhftbbmiltksr` view save

Test 19

Verdict: RUNTIME ERROR

input
`5 ab ababa b ca ...` view save

correct output
`ababaabbcaccb` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 20

Verdict: ACCEPTED

input
`5 o rjj sfj ti ...` view save

correct output
`orjjsfjtiw` view save

user output
`orjjsfjtiw` view save

Test 21

Verdict: RUNTIME ERROR

input
`5 a aa aaa abbab ...` view save

correct output
`aaaaaaabbabba` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 22

Verdict: ACCEPTED

input
`10 aoefh f ge hlmgh ...` view save

correct output
`aoefhfgehlmghimgjjjkmjmhhinmol...` view save

user output
`aoefhfgehlmghimgjjjkmjmhhinmol...` view save

Test 23

Verdict: ACCEPTED

input
`10 bcbec cjjil dbigk ei ...` view save

correct output
`bcbeccjjildbigkeifdigcgfbikfil...` view save

user output
`bcbeccjjildbigkeifdigcgfbikfil...` view save

Test 24

Verdict: ACCEPTED

input
`10 a cij d db ...` view save

correct output
`acijdbddhhekcgibfgglfffihkg` view save

user output
`acijdbddhhekcgibfgglfffihkg` view save

Test 25

Verdict: ACCEPTED

input
`10 ab d ebhin fk ...` view save

correct output
`abdebhinfkgjdinaiodgkacknab` view save

user output
`abdebhinfkgjdinaiodgkacknab` view save

Test 26

Verdict: ACCEPTED

input
`10 buywl fasgx gb jzpek ...` view save

correct output
`buywlfasgxgbjzpekoezwsoquaspfd...` view save

user output
`buywlfasgxgbjzpekoezwsoquaspfd...` view save

Test 27

Verdict: ACCEPTED

input
`10 acg bcggd dcg dede ...` view save

correct output
`acgbcggddcgdedeefcfdbbfgabbg` view save

user output
`acgbcggddcgdedeefcfdbbfgabbg` view save

Test 28

Verdict: ACCEPTED

input
`10 cmo cx dpr dtir ...` view save

correct output
`cmocxdprdtirhftbbmfmiltksrttkb...` view save

user output
`cmocxdprdtirhftbbmfmiltksrttkb...` view save

Test 29

Verdict: RUNTIME ERROR

input
`10 ab ababa abbc b ...` view save

correct output
`ababaababbcbbbcaccbcccccc` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 30

Verdict: ACCEPTED

input
`10 dmq gl j jqso ...` view save

correct output
`dmqgljjqsoorjjsfjtiulvw` view save

user output
`dmqgljjqsoorjjsfjtiulvw` view save

Test 31

Verdict: RUNTIME ERROR

input
`10 a aa aaa abbab ...` view save

correct output
`aaaaaaabbabbabbabbabbbbbabbbbb` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 32

Verdict: RUNTIME ERROR

input
`100 aa acmfac afmolcn alllbndbli ...` view save

correct output
`aaacmfacafmolcnalllbndbliamdal...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 33

Verdict: RUNTIME ERROR

input
`100 a acjgj ae aegdb ...` view save

correct output
`aacjgjaeaegdbafcbahledfchagaja...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 34

Verdict: RUNTIME ERROR

input
`100 a aah abaeeaifc abajl ...` view save

correct output
`aaahabaeeaifcabajlaehaejcdegka...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 35

Verdict: RUNTIME ERROR

input
`100 a aa abg abndfmmmk ...` view save

correct output
`aaaabgabndfmmmkacggjdeacogeada...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 36

Verdict: ACCEPTED

input
`100 afn aic ajrkgzldb amcyqyh ...` view save

correct output
`afnaicajrkgzldbamcyqyhandanxhj...` view save

user output
`afnaicajrkgzldbamcyqyhandanxhj...` view save

Test 37

Verdict: RUNTIME ERROR

input
`100 aacdeffdd abaacbae abfbbff ac ...` view save

correct output
`aacdeffddabaacbaeabfbbffacacbg...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 38

Verdict: ACCEPTED

input
`100 abnfxhutgk ajkdoqmdqp asxeblm badpwpsqhn ...` view save

correct output
`abnfxhutgkajkdoqmdqpasxeblmbad...` view save

user output
`abnfxhutgkajkdoqmdqpasxeblmbad...` view save

Test 39

Verdict: RUNTIME ERROR

input
`100 a aa aaaaacaca aaaabcabc ...` view save

correct output
`aaaaaaaacacaaaaabcabcaaabaaaab...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 40

Verdict: RUNTIME ERROR

input
`100 a aiesfhkro aivvkdc ajrtj ...` view save

correct output
`aaiesfhkroaivvkdcajrtjaqfnivlb...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 41

Verdict: RUNTIME ERROR

input
`100 a aa aaaa aaaaa ...` view save

correct output
`aaaaaaaaaaaaaaaaaaaaaaaaaaabab...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  [Previous line repeated 1 more time]
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 42

Verdict: RUNTIME ERROR

input
`200 a aa abbhjifdb acmfac ...` view save

correct output
`aaaabbhjifdbacmfacadiadnhkaehh...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 43

Verdict: RUNTIME ERROR

input
`200 a aa abihiahg acjgj ...` view save

correct output
`aaaabihiahgacjgjadaeaegdbafcba...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 44

Verdict: RUNTIME ERROR

input
`200 a aah abaeeaifc abajl ...` view save

correct output
`aaahabaeeaifcabajlaehaejcdegka...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 45

Verdict: RUNTIME ERROR

input
`200 a aa aan abg ...` view save

correct output
`aaaaanabgabndfmmmkacggjdeacoge...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 46

Verdict: RUNTIME ERROR

input
`200 ad aegewtfc afn aic ...` view save

correct output
`adaegewtfcafnaicajrkgzldbamcyq...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 47

Verdict: RUNTIME ERROR

input
`200 a aa aacdeffdd aaeceaeb ...` view save

correct output
`aaaaacdeffddaaeceaebabaacbaeab...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 48

Verdict: RUNTIME ERROR

input
`200 abnfxhutgk aghv ajkdoqmdqp ajpvvalnu ...` view save

correct output
`abnfxhutgkaghvajkdoqmdqpajpvva...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 49

Verdict: RUNTIME ERROR

input
`200 a aa aaaaacaca aaaabcabc ...` view save

correct output
`aaaaaaaacacaaaaabcabcaaaacbcaa...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 50

Verdict: RUNTIME ERROR

input
`200 a abam aiesfhkro aivvkdc ...` view save

correct output
`aabamaiesfhkroaivvkdcajrtjakam...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 51

Verdict: RUNTIME ERROR

input
`200 a aaicd acbjfaj achddjj ...` view save

correct output
`aaaicdacbjfajachddjjacifadaecf...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 52

Verdict: RUNTIME ERROR

input
`1000 a aa aaccbkcd aaj ...` view save

correct output
`aaaaaccbkcdaajaanabaabanikjabb...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 53

Verdict: RUNTIME ERROR

input
`1000 a aa aabecajcf aabg ...` view save

correct output
`aaaaabecajcfaabgaabjllgdlkaadg...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 54

Verdict: RUNTIME ERROR

input
`1000 a aa aablaga aah ...` view save

correct output
`aaaaablagaaahaajaaklkjjababaee...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 55

Verdict: RUNTIME ERROR

input
`1000 a aa aagjd aajdlmacjn ...` view save

correct output
`aaaaagjdaajdlmacjnaakjdngdfaal...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 56

Verdict: RUNTIME ERROR

input
`1000 a aalguz abcce abggxup ...` view save

correct output
`aaalguzabcceabggxupabujabxldxy...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 57

Verdict: RUNTIME ERROR

input
`1000 a aa aaabaaaaf aaaeb ...` view save

correct output
`aaaaaabaaaafaaaebaabeadaabfffd...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 58

Verdict: RUNTIME ERROR

input
`1000 a aamuthxggq abnfxhutgk adaumgqm ...` view save

correct output
`aaamuthxggqabnfxhutgkadaumgqma...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 59

Verdict: RUNTIME ERROR

input
`1000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaaaaaaaaaaaaaaabaa...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  [Previous line repeated 2 more times]
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 60

Verdict: RUNTIME ERROR

input
`1000 a aanmhqqnpc ab abam ...` view save

correct output
`aaanmhqqnpcababamabginwqvvacba...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 61

Verdict: RUNTIME ERROR

input
`1000 a aa aaaca aae ...` view save

correct output
`aaaaaacaaaeaaekcaagjeahdaahhdf...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 62

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaagle ...` view save

correct output
`aaaaaaaaaagleaaabaaabiaaaaccgh...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 63

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaagf ...` view save

correct output
`aaaaaaaaaagfaaaaihlblgaaaalkll...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 64

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaabkaaaaelbjbaaaaf...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 65

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaahleaaaajaaabaaab...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 66

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaacxrqz ...` view save

correct output
`aaaaaaaaacxrqzaaahaaaahaaaplto...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 67

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaaaaaaaaaadbaaaaaa...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  [Previous line repeated 2 more times]
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 68

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaail ...` view save

correct output
`aaaaaaaaailaaaitehaeaaaitxaaam...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 69

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaaabghaaaabcaffaaa...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 70

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaaggo ...` view save

correct output
`aaaaaaaaaaggoaaacwpgjkvaaaftbl...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Test 71

Verdict: RUNTIME ERROR

input
`100000 a aa aaa aaaa ...` view save

correct output
`aaaaaaaaaaaaaabaaaagkaaabaaabb...` view save

user output
(empty)

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 24, in <module>
    res += compare()
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 13, in compare
    return compare(j+1)
  File "/box/input/code.py", line 12, in compare
    if s1[0] == s2[len(s1)]:
IndexError: string index out of range

Aalto Competitive Programming 2026 - wk5 - Mon

Freight trains

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

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Test 24

Test 25

Test 26

Test 27

Test 28

Test 29

Test 30

Test 31

Test 32

Test 33

Test 34

Test 35

Test 36

Test 37

Test 38

Test 39

Test 40

Test 41

Test 42

Test 43

Test 44

Test 45

Test 46

Test 47

Test 48

Test 49

Test 50

Test 51

Test 52

Test 53

Test 54

Test 55

Test 56

Test 57

Test 58

Test 59

Test 60

Test 61

Test 62

Test 63

Test 64

Test 65

Test 66

Test 67

Test 68

Test 69

Test 70

Test 71

Tasks

Submissions (aalto26em_005)