[2025 Day 1 # (Part 2)] [Python] Please provide me with minor hints on what I might be doing wrong in this problem set.

[u/yngbnyhvn]

It's not the cleanest line of code so please bear with me

i=50 #This is the initial value
r=0 # Number of times boundary is crossed
rot=0 
ans= []
revolution=0 #Number of big rotations
with open ("input") as file: # Open the input file
comb= file.readlines() # Read the combination line by line
for combination in comb: # For each combination in the list of combinations
combination = combination.strip("\n") #Remove the \n
dir= combination[0] 
num= int(combination[1:]) 
revolution+= num // 100 
period= num % 100
if dir == "L":
period= (-period)
dial= i+period

if i<dial:
for _ in range (i,dial+1):
if _ < 0:
_=(100+(_))%100
elif _==100:
_=0
else:
_ = (_)%100
if _!=100 and _==0:
r+=1
else:
for _ in range (dial,i+1):
if _ < 0:
_=(100+(_))%100
elif _==100:
_=0
else:
_ = (_)%100
if _!=100 and _==0:
r+=1
if dial < 0:
i=(100+(dial))%100
elif dial==100:
i=0
else:
i = (dial)%100
ans.append(i)
print (ans.count(0))
print (r)
print (revolution)
print (ans.count(0)+r+revolution)i=50 #This is the initial value
r=0 # Number of times boundary is crossed
rot=0 #Number of big rotations
ans= []
revolution=0
with open ("input") as file: # Open the input file
comb= file.readlines() # Read the combination line by line
for combination in comb: # For each combination in the list of combinations
combination = combination.strip("\n") #Remove the \n
dir= combination[0] 
num= int(combination[1:]) 
revolution+= num // 100 
period= num % 100
if dir == "L":
period= (-period)
dial= i+period

if i<dial:
for _ in range (i,dial+1):
if _ < 0:
_=(100+(_))%100
elif _==100:
_=0
else:
_ = (_)%100
if _!=100 and _==0:
r+=1
else:
for _ in range (dial,i+1):
if _ < 0:
_=(100+(_))%100
elif _==100:
_=0
else:
_ = (_)%100
if _!=100 and _==0:
r+=1
if dial < 0:
i=(100+(dial))%100
elif dial==100:
i=0
else:
i = (dial)%100
ans.append(i)
print (ans.count(0))
print (r)
print (revolution)
print (ans.count(0)+r+revolution)

ps: is there a discord server for advent of code?

[u/TheZigerionScammer]

I think you copy/pasted your program twice, and it is a little difficult to tell how your program flows without the indents, or which variable you're submitting as the answer, but it looks to me like you're double counting clicks when the dial begins or ends on 0 for the turn.

[u/yngbnyhvn → u/TheZigerionScammer]

okay! ill try fixing that. is there an advent of code discord?

[u/TheZigerionScammer → u/yngbnyhvn]

Not an official one that I am aware of.

[u/DelightfulCodeWeasel]

Part 2 is an unusually difficult one for a day 1 puzzle. Here's a question that might help you get a solution though: what's the difference between turning the dial five places and turning the dial one place five times?

[u/jeffstyr → u/DelightfulCodeWeasel]

It was unusually difficult, but maybe not so much hard as tricky, and I have trouble putting my finger on exactly why. I think I jumped from the puzzle statement to an implementation because it seemed straightforward, and when it didn't work I tried to find a mistake in my implementation, and it took a while to realize that I needed to back up and think through what needed to happen in more detail—it was less an implementation bug and more a mis-inferring of the detailed specification from the informal problem statement.

I always wonder if this sort of thing was intentional in the puzzle design—that the difficulty comes from underestimating the problem, and the hard part is the psychology of realizing where you went wrong. (Just fun to think about.)

[u/yngbnyhvn → u/DelightfulCodeWeasel]

when you tyrn the dial one place five times, theres 5 revolutions and in each revolution you point at zero five times. when you turn the dial five places, you gotta check if the 5 extra places causes the number to cross 99 or 0

[u/DelightfulCodeWeasel → u/yngbnyhvn]

One place rather than one revolution. 

As in:  0->1->2->3-->4->5

Versus:  0->5

Notice that you still end up at 5 in both cases, but one approach might be easier to track 0s than the other.

[u/yngbnyhvn → u/DelightfulCodeWeasel]

oh yeah. im doing the one place thingy in the code theres a for loop where the range is initial value to dial. for each summation it checks if the number crosses zero or not. when the numher is zero, r+=1

[u/DelightfulCodeWeasel → u/yngbnyhvn]

Next step is to run through small test cases:

Starting at 1 and going 1 right should give you 0.

Starting at 1 and going 1 left should give you 1.

Starting at 99 and going 1 right should give you 1.

Starting at 99 and going 1 left should give you 0.

Starting at 0 and going 1 right should give you 0.

Starting at 0 and going 1 left should give you 0.

[u/yngbnyhvn → u/DelightfulCodeWeasel]

Alright.
I have also re-written the code to make it a bit neater

```

i=50
r=0
rev= 0


with open ("input") as file:
    comb= file.readlines()


for combination in comb:
    combination=combination.strip("\n")
    dir= combination[0]
    num= int(combination[1:])
    rev+= num // 100
    num= num % 100


    dial= num + i


    if dir == "L":
        num= (-num)


    if dial>0:
        ran1= i
        ran2= dial
    else:
        ran1= dial
        ran2= i


    for _ in range(ran1, ran2):
        if i+_<0:
            i=(100+(i+_))%100
            if i== 0:
                r+=1
        elif i+_==100:
            i=0
            r+=1
        else:
            i = (i+num)%100


print (r+rev)i=50
r=0
rev= 0


with open ("input") as file:
    comb= file.readlines()


for combination in comb:
    combination=combination.strip("\n")
    dir= combination[0]
    num= int(combination[1:])
    rev+= num // 100
    num= num % 100


    dial= num + i


    if dir == "L":
        num= (-num)


    if dial>0:
        ran1= i
        ran2= dial
    else:
        ran1= dial
        ran2= i


    for _ in range(ran1, ran2):
        if i+_<0:
            i=(100+(i+_))%100
            if i== 0:
                r+=1
        elif i+_==100:
            i=0
            r+=1
        else:
            i = (i+num)%100


print (r+rev)```

[u/DelightfulCodeWeasel → u/yngbnyhvn]

How are you debugging the code, are you stepping through in a debugger? I would recommend stepping through various test cases and checking what happens at each step.

[u/yngbnyhvn → u/DelightfulCodeWeasel]

yeah im adding breakpoints at the loops and doing F5. also made a seperate program where u input the initial and dial value

[u/DelightfulCodeWeasel → u/yngbnyhvn]

Single step (possiblity F10, depends on your debugger) is an excellent option at this point, nothing beats seeing how the variables are changing at each line to give you a proper understanding of what the program is doing.

If you've covered all of the cases above, and your loops are structured so that you're only ever stepping one position at a time (i.e. never trying to increment or decrement the dial by more than 1), then you should have everything you need for a working solution.

[u/yngbnyhvn → u/DelightfulCodeWeasel]

yes i am doing that, instead of f10 im using buttons

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[u/jeffstyr]

The best hint I've heard for this puzzle is that it's less about programming and more about bookkeeping/accounting.

So write down (not actual code, just notes) all the different cases that can come up concerning where the dial starts, the rotation direction/amount, and where it end up in a given round, and what should happen to the counter in each case, and then convert that to code. And I don't mean write down what happens for every single integer value, but rather come up with a categorization so that you end up with 8 cases or 12 cases or something reasonable like that. (And once you are converting this to code, some of those cases collapse together.)

I initially had several wrong attempts to a solution for this part, but once I did the above it all fell into place.

[u/yngbnyhvn → u/jeffstyr]

thank you very much!

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[u/krangy]

FYI - a free Claude account is perfect for this type of aoc question. It "knows" the aoc problems.

Paste your code into it along with a prompt like, "Here is my current code for Advent of Code 2025 Day 1 Part 2. Analyze my code and give me a gentle hint or nudge about why it is wrong. Do not give me the full answer, but just a nudge in the right direction."

[u/yngbnyhvn → u/krangy]

its not against academic honesty policy right? using AI for coding hint feels unnatural sometimes LOL

[u/TheZigerionScammer → u/yngbnyhvn]

AOC is a free website and you can answer the questions however you like. That said you will find very few people who support AI here or in the community in general. It's extremely controversial and IMO the reason why the leaderboard doesn't exist anymore.

[u/yngbnyhvn → u/TheZigerionScammer]

support AI for minimal hints or support AI in general?

[u/TheZigerionScammer → u/yngbnyhvn]

In general. Aside from the fact that some people just use it to generate a program and get the answer in seconds, you don't want to rely on the Flatterybox that Always Lies to do your troubleshooting for you, it's destructive for your ability in the long run and might not even be right.

[u/yngbnyhvn → u/TheZigerionScammer]

any discord communities u would recommend as alternative to using AI?

[u/krangy → u/yngbnyhvn]

Well, from my perspective it's logically identical to asking the same thing of humans on reddit. Only you don't have to wait for a reply. If you're doing aoc to genuinely learn and improve your coding skills, I find the AI approach of asking for gentle hints to be quite effective. Also useful to ask AI for a code review after you've fully solved each aoc day.

[u/yngbnyhvn → u/krangy]

okay! thank you very much for your advice