Advent of Code 2025 Day 4 (BaseA Style)

[AlteryxMatt]

Discussion thread for day 4 of the Advent of Code - https://adventofcode.com/2025/day/4

[lwolfie]

2 Stars again!

[kelly_gilbert]

This one was fun!

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Outer workflow:





Iterative macro:
Iterates until there are no more moveable rolls.

[Yoshiro_Fujimori]

My solution.

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Main Workflow

Macro

[Desmond]

Blunt force to solve part two, should have built a macro but I expected it to take less iterations to get to the answer so away I went with the copy and paste method...

[mkeiffer]

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  Scrambling to get caught up!

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[CoG]

For those who despise both macros and your own sanity but love Base-A AoC, then look no further because P2 can indeed be solved without a macro. The downside is that the solution is over-complicated and much slower (4x slower for me).

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It looks deceptively simple, and you can continue to live in that blissful ignorance as long as you do not open the Generate Rows Tool :)

Practically, speaking the solution isn't really that complex, it's just the implementation that gets you. It's a lot of RegEx covering every possible case of a paper roll being surrounded by 0-3 other rolls of paper. REGEX_Match() looks for the pattern and REGEX_Replace() removes the roll. I tried to optimize everything as much as I could think to, but it's still quite complicated.

I hope y'all are enjoying Advent of Code as much as I am. Happy Solving (again)!

[Carolyn]

Solved!

Since AoC involves a lot of walking to adjacent squares, I went ahead and built a macro to find all the adjacent spots, with the ability to include/exclude the diagonal squares.

From there, nothing too crazy. Within the iterative macro, I added a Count to compare the initial records with the final records in an iteration so that way it's really easy to identify when nothing is removed.

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[JoshuaB]

This is part 1, I'm working on a non-macro path for part 2

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[martinson]

Part 1

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Part 2

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[estherb47]

Enjoyed this one!

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In years past, I've done these types of challenges as spatial. So in the vein of trying something new, decided to go a different route.

Used the multi-row tool to find up to 8 neighbors for each location, identified what should be removed, rebuilt the rows.

The sort is key to the multi-row tool.