CSES - Aalto Competitive Programming 2026 - wk1 - Mon

Submission details
Task:	Babaza Game
Sender:	aalto26am_033
Submission time:	2026-08-31 23:24:16 +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	RUNTIME ERROR	0.06 s	details
#5	ACCEPTED	0.04 s	details
#6	ACCEPTED	0.04 s	details
#7	RUNTIME ERROR	0.06 s	details
#8	RUNTIME ERROR	0.06 s	details
#9	ACCEPTED	0.04 s	details
#10	ACCEPTED	0.04 s	details
#11	ACCEPTED	0.04 s	details
#12	RUNTIME ERROR	0.06 s	details
#13	ACCEPTED	0.04 s	details
#14	RUNTIME ERROR	0.06 s	details

Code

def bestStep(start: str, goal: str):
    print(start)
    if start != goal:
        oneMove = True
        for i in range(0,len(start)-1):
            oneMove = oneMove and (start[i] == goal[i] or start[i+1] == goal[i+1])
        if oneMove:
            return bestStep(goal,goal)
        blocked = [False for i in range(0,len(start))]
        for i in range(0,len(start)-1):
            blocked[i] = blocked[i]     or (start[i+1] == goal[i])
            blocked[i+1] = blocked[i+1] or (start[i] == goal[i+1])
        twoMove = True
        for i in range(0,len(start)-1):
            twoMove = twoMove and (not blocked[i] or not blocked[i+1])
        free = list(set(list(map(chr, range(ord('A'), ord('Z')+1)))).difference(set(list(start)).union(set(list(goal)))))[0]
        if twoMove:
            def helper(i):
                if blocked[i]: 
                    return start[i] 
                else: 
                    if i != len(blocked):
                        blocked[i+1] = True
                    return goal[i]
            
            return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
        def helper2(i):
            if ((i%2) == 1): 
                return free 
            else: 
                return start[i]
        return bestStep(''.join([helper2(i) for i in range(0,len(start))]),goal)
                
                

bestStep(input(),input())

Test details

Test 1

Verdict: ACCEPTED

input
`A B` view save

correct output
`A B` view save

user output
`A B` view save

Test 2

Verdict: ACCEPTED

input
`BABAZA BACBCB` view save

correct output
`BABAZA BACACA BACBCB` view save

user output
`BABAZA BACACA BACBCB` view save

Test 3

Verdict: ACCEPTED

input
`AB BA` view save

correct output
`AB CB CA BA` view save

user output
`AB AC BC BA` view save

Test 4

Verdict: RUNTIME ERROR

input
`ABC BCD` view save

correct output
`ABC DBD DCD BCD` view save

user output
`ABC AEC` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 37, in <module>
    bestStep(input(),input())
  File "/box/input/code.py", line 33, in bestStep
    return bestStep(''.join([helper2(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in bestStep
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in <listcomp>
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 24, in helper
    blocked[i+1] = True
IndexError: list index out of range

Test 5

Verdict: ACCEPTED

input
`AXYB CXYD` view save

correct output
`AXYB CXYD` view save

user output
`AXYB CXYD` view save

Test 6

Verdict: ACCEPTED

input
`LMIJLF PAQBMH` view save

correct output
`LMIJLF PMQJMF PAQBMH` view save

user output
`LMIJLF PMQJMF PAQBMH` view save

Test 7

Verdict: RUNTIME ERROR

input
`PNIWLSLIH CRLVPUFHD` view save

correct output
`PNIWLSLIH CNLWPSFID CRLVPUFHD` view save

user output
`PNIWLSLIH` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 37, in <module>
    bestStep(input(),input())
  File "/box/input/code.py", line 27, in bestStep
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in <listcomp>
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 24, in helper
    blocked[i+1] = True
IndexError: list index out of range

Test 8

Verdict: RUNTIME ERROR

input
`ZDYIAVTKL ZJKVXGAUM` view save

correct output
`ZDYIAVTKL ZJYVAGTUL ZJKVXGAUM` view save

user output
`ZDYIAVTKL` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 37, in <module>
    bestStep(input(),input())
  File "/box/input/code.py", line 27, in bestStep
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in <listcomp>
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 24, in helper
    blocked[i+1] = True
IndexError: list index out of range

Test 9

Verdict: ACCEPTED

input
`FBIXISJH NXZIESMG` view save

correct output
`FBIXISJH NBZXESMH NXZIESMG` view save

user output
`FBIXISJH NBZXESMH NXZIESMG` view save

Test 10

Verdict: ACCEPTED

input
`OPGW QJIE` view save

correct output
`OPGW QPIW QJIE` view save

user output
`OPGW QPIW QJIE` view save

Test 11

Verdict: ACCEPTED

input
`DUKNPKQZBL NZPBMOEBIC` view save

correct output
`DUKNPKQZBL NUPNMKEZIL NZPBMOEBIC` view save

user output
`DUKNPKQZBL NUPNMKEZIL NZPBMOEBIC` view save

Test 12

Verdict: RUNTIME ERROR

input
`ZWDTX HZOXI` view save

correct output
`ZWDTX HWOTI HZOXI` view save

user output
`ZWDTX` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 37, in <module>
    bestStep(input(),input())
  File "/box/input/code.py", line 27, in bestStep
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in <listcomp>
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 24, in helper
    blocked[i+1] = True
IndexError: list index out of range

Test 13

Verdict: ACCEPTED

input
`URJF ITIQ` view save

correct output
`URJF IRIF ITIQ` view save

user output
`URJF IRIF ITIQ` view save

Test 14

Verdict: RUNTIME ERROR

input
`WYWBWU IRYVBA` view save

correct output
`WYWBWU WRWVWA IRYVBA` view save

user output
`WYWBWU` view save

Error:

Traceback (most recent call last):
  File "/box/input/code.py", line 37, in <module>
    bestStep(input(),input())
  File "/box/input/code.py", line 27, in bestStep
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 27, in <listcomp>
    return bestStep(''.join([helper(i) for i in range(0,len(start))]),goal)
  File "/box/input/code.py", line 24, in helper
    blocked[i+1] = True
IndexError: list index out of range

Aalto Competitive Programming 2026 - wk1 - Mon

Babaza Game

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

Tasks

Submissions (aalto26am_033)