As suspected, @gawa, copied my solution before I even finished it XD. Well done, sir! This was a surprisingly simple problem (maybe could have swapped for Day 6?). Another excellent algorithm lesson
Spoiler
Both parts of this problem are solved via an algorithm known as Breadth First Search ([BFS]: where all nearest neighbors are evaluated for every point in the queue, valid next steps are kept, and all other paths are terminated). To use this problem as an example start with all 0's (Trailheads) in the dataset, and create an iterative macro that does the following: first, check the left, right, top, and bottom neighbors for all 0's, only keep 1's, on the next iteration do the same, but only keep 2's, etc. until 9, at which point you are done. This output actually solves Part 2 first, with part 1 needing a little bit of extra work to achieve the answer. Simple problem + simple workflow = Great Day!
Main Workflow:
BFS Macro:
Main Workflow:
BFS Macro:
The best part2 is the one you already solved while doing part 1. 
Spoiler
This one lined up with the way I like to work with grids. Also highlights how it is sometimes easier to just code all the cases than get fancy with generate rows and associated formulas.
Sadly, a Macro input configuration caused me to have to rebuild the macro and kept me out of 1k again. The struggle continues.
Sadly, a Macro input configuration caused me to have to rebuild the macro and kept me out of 1k again. The struggle continues.
Spoiler
 
today challenge is like design for alteryx.
just a tool different, so i use detour instead.
Spoiler
part1: loop 0 to 9, use summarise to unique the same location
part2: do not unique it. (which for me, do not summarise it.)
part2: do not unique it. (which for me, do not summarise it.)
I *distinctly* remember someone (looking at you @CoG ) telling me to read the constraints carefully. I think many people (including myself) solved part 2 first 😂
Spoiler
Since I'm tired and didn't annotate my flow:
Added a "y" coordinate with 1st record tool
Regex Tokenize to Rows on \d
Select Tool to change the Topo field to byte
Multi-Row Grouped on "y" coordinate to add "x"
Split Trailheads (0's) from Trails and give each a TrailheadId
Send trailhead to macro and rest of trail to second input for macro
In the macro take the coordinates from the head and determine 1 left, right, up, and down (formula). Don't forget to constrain your moves to the First-Last Column and Row. Don't want to go out of bounds. Achieved with IF statements.
Join new coordinates to trail set
Use Filters to keep only the next relevant Topo value. Here is here iteration number is valuable for increasing the value dynamically each run.
union all the True streams (Of course I could have applied union first and used less filter tools, but meh - again tired.
Check to see if you've reached the last Topo level and send to output, otherwise return to run the next level.
Coming out of the macro you have ALL possibilities to get from a Trailhead to 9, but Part 1 wants Trailhead to Unique 9's. So apply a Unique tool by TrailheadID on the coordinate for level 9. Answer is record count.
For part 2 the ask is to sum the ratings which is made up of ALL possible paths to get from Trailhead to a 9. So take the pre-Unique tool record count..
Day 10 Part 1 & 2 w Iterative Macro
Added a "y" coordinate with 1st record tool
Regex Tokenize to Rows on \d
Select Tool to change the Topo field to byte
Multi-Row Grouped on "y" coordinate to add "x"
Split Trailheads (0's) from Trails and give each a TrailheadId
Send trailhead to macro and rest of trail to second input for macro
In the macro take the coordinates from the head and determine 1 left, right, up, and down (formula). Don't forget to constrain your moves to the First-Last Column and Row. Don't want to go out of bounds. Achieved with IF statements.
Join new coordinates to trail set
Use Filters to keep only the next relevant Topo value. Here is here iteration number is valuable for increasing the value dynamically each run.
union all the True streams (Of course I could have applied union first and used less filter tools, but meh - again tired.
Check to see if you've reached the last Topo level and send to output, otherwise return to run the next level.
Coming out of the macro you have ALL possibilities to get from a Trailhead to 9, but Part 1 wants Trailhead to Unique 9's. So apply a Unique tool by TrailheadID on the coordinate for level 9. Answer is record count.
For part 2 the ask is to sum the ratings which is made up of ALL possible paths to get from Trailhead to a 9. So take the pre-Unique tool record count..
Day 10 Part 1 & 2 w Iterative Macro
