Advent of Code 2025 Day 9 (BaseA Style)

[AlteryxCommunityTeam]

Discussion thread for day 9 of the Advent of Code - https://adventofcode.com/2025/day/9

[Qiu]

Really need to learn more about Spatial Tools. 😁

[danboll_life]

I was surprised that the Spatial tools didn't return the correct answer.

Spoiler

[EKasminsky]

Spoiler

Part 1 solved.. not sure on part 2.

[estherb47]

Today the strangest thing happened to me. Part 1 solved easily with Spatial tools. And without (you can generate all of the points in an area with two generate rows tools, but that's TORTOISE levels of slow.

My spatial approach looked valid. Checked everything multiple times. All was in order. Thought perhaps I had exceeded the limit of integer spatial points, but nope. Thought I had forgotten to set data types correctly. Nope.

Before going the slow route, recreated my part 2 in a new workflow. Step for step, the same. And tada! The answer was correct. Somehow the first and second largest were inverted in the first workflow. Same exact tools, same exact order. Same formulas came up with different values for the combination of points.

I have to delete and burn my first workflow. Clearly, it's cursed.

Spoiler

Straightforward spatial analysis. Don't forget that the lat/lon are integers.

I can't upload my workflow from my work computer. Will do so when I recreate on my home laptop

[mkeiffer]

My Day 9 solution! 

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[Pilsner]

Here's my day 9 workflow. I faced similar challenges to others with fractional overhang on some of the regions, but still loved the opportunity to use the spatial tools again!

Spoiler

I will post a tidier version + write up at a later date, uploading this now so I have all challenges submitted by the end of day 12.