Tootfinder

A nice bump in difficulty for today's #AdventOfCode problem!
Although the first part came to me very easily, I spent way too much time trying to implement a flooding algorithm for part 2, only to find out that it would take too much time and there should be a better way.
The worst part is that I had the intuition for my final solution super early on, but couldn't materialize it in a simple way until tonight.
I also must admit I realized quite late that the points were sorted in the input :D I should RTFM better sometimes.
My final #rust solution runs very quickly and is reasonably clean.
#AoC #AoC2025 #AdventOfCode2025 #RustLang

Yes! Today's puzzle in #AdventOfCode was quite hard (especially part 2) but so rewarding and I learned a lot!
For part 1, I implemented A* from scratch, my favorite little pathfinding algo that I use pretty much every year for #AoC (sometimes I use a lib instead of implementing it but it's been a while so a refresher was in order).
For part 2, after trying A* again and noticing it was running for way too long, I went back to the drawing board and solved the first machine by hand. I noticed the constraints were a system of linear equations.
I then researched algorithms to solve such integer programming problems and didn't feel like learning AND implementing the algorithms in one day (ain't nobody got time fo that). But this lead me to discover the `good_lp` #rust crate which is really good and that I will keep in my back pocket from now on!
So I used the library to define a system of variables and constraints which could be solved magically for me.
#AoC2025 #AdventOfCode2025 #RustLang

A cool graph problem today in #AdventOfCode
Nothing special here, I leveraged the `petgraph` #rust crate which I love! Calculating all pairs' distances (squared) and joining the pairs that are closest with an edge.
Only thing I wish I had more time to implement would be the graph traversal algo during sub-net aggregation, but swamped with work at the moment.
#AoC #AoC2025 #AdventOfCode2025 #RustLang

Today's puzzle in #AdventOfCode was another grid puzzle, where I again represented the entities as a sparse set.
Part 1 was relatively straightforward, a simplified BFS-like process allowed to construct the beams going through the system.
For part 2, additionally to gathering where a beam was present, I added metadata about how many paths were going through each position, adding them up and splitting them as required. Summing the paths for the last row gave the required result.
#AoC #AoC2025 #AdventOfCode2025 #RustLang #rust

Today's #AdventOfCode problem was more about parsing than about complex logic, but it was fun!
I opted to keep the parsing with winnow simple and do most of it by hand from the raw characters, to exercise my #rust iterators a bit.
#AoC #AoC2025 #AdventOfCode2025 #RustLang

Another easy challenge in today's #AdventOfCode puzzle.
Part 1 is straightforward, and for part 2, the trick was to sort the list of ID ranges first, which made the merging pretty easy.
#AoC #AoC2025 #AdventOfCode2025 #rust #RustLang

Didn't feel like thinking too much for today's problem of #AdventOfCode, so my solution is quite naive and runs in a few tens of milliseconds for part 2 (thanks, #RustLang!).
I went for a HashSet for the grid just because it made looking up neighbours simpler at the edges, probably also not the most performant solution, but gets better as the grid becomes sparser.
#AoC #AoC2025 #AdventOfCode2025 #rust

Super happy with my solution for today's #AdventOfCode problem!
It initially took me a little bit of time to find a suitable strategy, but it all clicked when I noticed that the left-most selected digit had the most significance in the final value. Thus, I maximized the value of that left-most digit, leaving enough digits on the right side to be able to pick the required total number of batteries in the bank.
The solution is relatively short and sweet:
#AdventOfCode2025 #AoC #AoC2025 #RustLang #rust

Today's #AdventOfCode problem was fun! I kept a different implementation for part 1 vs part 2 as they both run relatively fast.
For part 1, I iterated over all IDs (the ranges are quite small) and split them in half mathematically (no string representation) to compare both halves.
For part 2, I instead generated all interestings IDs (mathematically again) up to a length of 10 digits (the max in my input) and checked if any of the ranges contained them.
#AoC #AoC2025 #AdventOfCode2025 #RustLang #rust

Day 11 of #AdventOfCode is a classical graph problem like we're used to from previous years.
Unlike previously, I immediately thought of checking what the graph looked like with a visualization tool. Luckily, `petgraph` allows to export a graphviz file which can be then used to visualize the nodes and edges.
From that, it was clear that a few nodes were acting as "bridges" between largers subnets of nodes with no particular arrangement besides being directed towards the next "bridge" layer. Those bridge layers comprised 4 to 5 nodes in my input, and were the only ones with more than 6 incoming edges, so I used that as my filter criterion.
To gather them, I sorted the graph in topological order and chunked them by their position offset compared to the previous node. When doing this, all the nodes from a bridge layer end up being at most 20 positions away from the previous node in the sorted list.
Finally, I progressed through each subnet, collecting information about how many paths lead to each one of the end layer's nodes. By multiplying with all the paths leading to each start layer's node, we get the overall total number of paths.
#AoC #AoC2025 #AdventOfCode2025 #RustLang #rust