aoc2025

My Advent of Code 2025 attempt

Good luck to everyone trying!

Notes

Day 0

• I've put input.txt into my .gitignore to be a better AOC participant. In the past, I committed input data, but apparantly the creator of AOC doesn't want input data to be aggregatable (so putting it online in a repo isn't so great)
• I haven't decided what language for this year. I am noodling around with using multiple languages, whatever is easiest for the challenge of the day.
• I will be using aocd for helping with fetching input data and example data. This simplifies the data wrangling - in the past I've coded crude data fetchers but this year, I'm just going to focus on the puzzles themselves.

Day 1

Part 1

• Decided to use excel
• new functions I encountered: flash fill, nested IF's, MOD, QUOTIENT
• trickiest part was to think in both 0 index and 1 index - the counting system of the problem is 0-99, but the number system that I'm used to is 1-100 so I had to do some trial and error to get the right overflow behaviour
• if I were programming it, I'd either use
  • an array with bounds checking
  • or a ring buffer. I had a ring buffer implementation in c from a previous course ELEX 8030, all I would need to do is to set the ring size, and let the "ring" mechanism take care of the looping/overflow, and the "data" being stored in the ring would be the count of times when the buffer is empty. Part 2 can be accomplished by adding some checking to the code where the ring loops back and forth on itself.
  • OR it could be a stack where you push and pop.
  • Lots of interesting data structures to use with this problem.
• using excel was a blessing in disguise because I had access to a bunch of easy to use built in functions so I don't have to code it all

Part 2

• going to do this tomorrow.