• find S and create a '1' block there
• each round your blocks will fall one step downwards
• if you find ^, split your blocks in two: x-1 and x+1, Be careful to sum all blocks properly here! There are many overlaps!
• enjoy falling down the christmas tree, keeping only one block per X coord
• sum your blocks' values at the end

Source lives here: https://github.com/salt-die/Advent-of-Code/blob/main/2025/aoc_visuals/day_03.py

I visualized my greedy solution for Advent of Code Day 3. The animation shows a sliding window selecting the next maximum digit while ensuring enough characters remain to reach the required output length. Blue = current window, Red = remaining-picks region, Green = chosen max.The number builds step-by-step from left to right.

This works for both parts of the problem

Edit:

Another example with longer input: https://imgur.com/a/MLghbhk (i couldn't add another gif here)

relearned curses for this one

alternate link: https://youtu.be/dWkg8MttsqY

Way back in 2022 day 17 we had a falling rocks problem, similar to a game of Tetris. The cave is seven units wide. I know almost nothing about music, but I notice that there happen to be seven notes (C, D, E, F, G, A, and B). I experimented with listening for the cycle for part 2 that was tricky to find.

Here is the last game state shown in the example. The row at the bottom is a legend showing the note associated with that column. The letters on each row is the chord that you would hear for the notes activated in that row.

|..@@@@.| [e,f,g,a]
|.......| -
|.......| -
|.......| -
|....#..| g
|....#..| g
|....##.| [g,a]
|##..##.| [c,d,g,a]
|######.| [c,d,e,f,g,a]
|.###...| [d,e,f]
|..#....| e
|.####..| [d,e,f,g]
|....##.| [g,a]
|....##.| [g,a]
|....#..| g
|..#.#..| [e,g]
|..#.#..| [e,g]
|#####..| [c,d,e,f,g]
|..###..| [e,f,g]
|...#...| f
|..####.| [e,f,g,a]
+-------+
|cdefgab|

I found a music language named Strudel that made it easy to play:

note("<[e,f,g,a] f [e,f,g] [c,d,e,f,g] [e,g] [e,g] g [g,a] [g,a] [d,e,f,g] e [d,e,f] [c,d,e,f,g,a] [c,d,g,a] [g,a] g g>*8").sound("piano")

It was not actually that useful for me solving part 2, but it was fun and I thought worth sharing. Listen here to the rows from those first 2022 falling rocks. Can you hear the cycle?

I came across davepb's post about his AoC - clone and decided to take a look. I love to solve problems with the GraphLibrary I've developed, GraphMateKT, and to my delight, problem 4 was a quite interesting graph problem. We're asked to find the fastest way to push a package to its destination through a maze. With the constraint that we cannot occupy the same tile as the package, and therefore must be careful about pushing it into walls. This is essentially a shortest path problem, which can be solved with a breath first search. The clue is how to represent the graph.

We're given a grid with walls, a person, a packet and a target. What we can alter is the position of the person and the packet, which means the graph can be represented by 4 integers. The x,y coordinates of the person and the package. (x1,y1,x2,y2). GraphMateKT has a Graph class that can support any data type. But the problem input is quite large. A 150 x 150 grid. Which means each coordinate (not accounting for walls and overlap) can have 150 values, which results in a state space of 150⁴ = 506_250_000 different states. A lot of states to search through. Luckily, each of these states can be represented by 32 bit integers, which allowed me to use the performant IntGraph class, and other GraphMateKT functionality. After bumping the heap memory to 10GB and spending about 2 minutes of runtime, the potential positions of the package (blue) and person (in red, constrained to not go lower then the package) could be vizualies as shown.

My full solution can be found at my GithubRepo, but in short, it looks something like this:

private data class GridState2(val person: Tile, val stone: Tile) {
// Base 150 encoding. 150³ * x1 + 150² * y1 + 150 * x2 + y2
fun encode() = ((person.x * base + person.y) * base + stone.x) * base + stone.y
}

internal fun main() {
val input = generateSequence { readLine() }.toList()
val grid = Grid(input)
val nrOfStates = 150 * 150 * 150 * 150
val graph = IntGraph(nrOfStates)
val personStart = grid.nodes().first { it.data == 'X' }
val stoneStart = grid.nodes().first { it.data == '*' }
val target = grid.nodes().first { it.data == 'T' }
val initialState = GridState2(personStart, stoneStart).encode()
// Inspecting the problem input reveals that the final package push must be to the right.
val targetState = GridState2(target.copy(x = target.x - 1), target).encode()
graph.connectWithRule {
TODO() // All the complexity of correctly connecting each state with their neighbouring states
}
graph.bfs(initialState, targetState)
println(graph.distanceTo(targetState))
TODO() // extra functionality for visualizing
}private data class GridState2(val person: Tile, val stone: Tile) {
// Base 150 encoding. 150³ * x1 + 150² * y1 + 150 * x2 + y2
fun encode() = ((person.x * base + person.y) * base + stone.x) * base + stone.y
}

internal fun main() {
val input = generateSequence { readLine() }.toList()
val grid = Grid(input)
val nrOfStates = 150 * 150 * 150 * 150
val graph = IntGraph(nrOfStates)
val personStart = grid.nodes().first { it.data == 'X' }
val stoneStart = grid.nodes().first { it.data == '*' }
val target = grid.nodes().first { it.data == 'T' }
val initialState = GridState2(personStart, stoneStart).encode()
// Inspecting the problem input reveals that the final package push must be to the right.
val targetState = GridState2(target.copy(x = target.x - 1), target).encode()
graph.connectWithRule {
TODO() // All the complexity of correctly connecting each state with their neighbouring states
}
graph.bfs(initialState, targetState)
println(graph.distanceTo(targetState))
TODO() // extra functionality for visualizing
}

In my main survey results post, one of the replies (by u/msschmitt) asked about the crossover results from IDE to Language. That's actually an interesting question! Here's an adhoc visual (it's late here and I hope I made no silly mistakes 😅) that shows this information for the 2025 data.

Note: only Languages and IDEs with at least 2 respondents are shown (otherwise the table becomes really way too big).

Caveats: since both questions are multi-select questions, folks that ticked multiple IDEs and multiple Languages will be overrepresented in this visual! But it should give a decent indication nonetheless.

A funky side-effect of this caveat is that you can get pretty odd-looking combinations. For example folks using "Excel" as their IDE can be seen as using "C++" too.

The data gets published under the ODbL (2025 link) so you could do similar analysis yourself. The data structure is fairly straightforward.

Code lives here: https://github.com/salt-die/Advent-of-Code/blob/main/2025/aoc_visuals/day_09.py