I didn’t do any optimisation. Made something to better track how long it takes for the solutions to run. I felt like by the time it took to implement the optimisation, the program would have ended by then.

I only save TDB from making sure seed ranges are unique. Would be 15,845,578,766 total seeds and that took 48 mins 22 secs 842 ms (with only Notepad++ and command prompt running). Is saving of TBD% (rounded to 2 dp).

Edit: there was a bug.

Edited 2023-12-05 21:24:50

wow the difference between day 5 and 6 😂 I'm surprised they made the input so short and brute-forceable

I thought day 6 could be so easy I could do it while bevvied. Is just 2 arrays, times and differences. For each possible time, compare how long is possible to go.

Spoilers below for anyone that hasn't done it yet:

Or you can break out the quadratic formula for a more direct solution without iteration :)

Edited 2023-12-06 19:04:16

I am already falling behind, was bug fixing till 4:00 AM for day 3, second problem...

I am slowly regretting using C... lmao

Edited 2023-12-06 21:32:28

i think the real challenge of day 6 is to halve the number of iterations. It's a bell curve.

Is day 8 part 2 another of these CPU intensive tasks? Before was just day 5 part 2.

Yes, in the sense that the computation complexity serves as a restriction to motivate participants to make a smarter algorithm for the task.
No, in the sense that it cannot be brute forced, as "easily" as day 5.

I don’t know another way to solve it. My program has been running for about 2 hours.

Uses a while loop which contains a for loop to follow the complete path from the starts to an end.

You are expected to notice, that each of the ghosts starts visiting the same (for him) exit node again and again after certain amount of steps, i.e. that he is wandering in loops. The task is to identify those loops for each of the ghosts, and calculate the step count, where all the loops simultaneously end on the exit nodes.

Do you only need to find out where each ghost’s path end and do a calculation based on that?

The paths of each of the ghost are infinite. You need to identify loops for each of the ghosts:
- exit node
- step, when the ghost lands on the exit node
- loop size: steps between each revisit of the end node

Having those data on each of the loops allows for a quick calculation, on when all loops will converge

Based on the output I got after the optimisation, the number is way to high to go through one at a time. It's more likely for my laptop to randomly crash before getting the answer.

I left GCSE maths buried in the past.

My answer is in the 10s of trillions.

Everything up to this part I didnt need google for.

Edited 2023-12-08 16:10:04

Anyone doing Hanukkah of Data/Noah's Rug this year?

Never heard of those.

Day 9 was disappointingly easy. Or maybe I got too lucky, that my straight implementation didnt encounter any hidden issues.

Edited 2023-12-09 15:57:31

Multiple levels of arrays are confusing.

Has the WZ AoC interest ran out of steam? Besides me, there is barely any star-progression during the past week.

I’m away for until sometime next week. Can’t exactly code on mobile.