Advent of Code 2021 Day 5 (BaseA Style)

Discussion thread for day 5 of the Advent of Code - https://adventofcode.com/2021/day/5

Accepted answers

All comments

I guess my teachers were right and we did need to remember y = mx + b. A great opportunity to use the generate rows tool!

Spoiler

Step 1: Parse out the lines
Challenge 1:
Step 2: Fitler for just horizontal and vertical
Step 3: Generate X positions
Step 4: Generate Y Positions
Step 4: Group by X,Ys of generated positions and count
Step 5: Filter for any > 1
Challenge 2:
Step 2: Calculate m and b
Step 3: Generate X positions
Step 4: Calculate y using y = mx + b
Step 4: Group by X,Ys of generated positions and count
Step 5: Filter for any > 1'

Day 5 Solution.yxzp

clmc9601

Lots of Generate Rows!

Spoiler

Screen Shot 2021-12-04 at 10.41.49 PM.png

cgoodman

Spoiler

Again another day where the part two wasn't that much more difficult than the first part. I just got stuck down a rabbit hole as the first attempt at building it out I had forgotten that there could be diagonals in both directions, so it's not just as case of generating the x.y co-ordinates as you need to factor in increasing and decreasing values in x and y and because I was using a join based on position instead of calculating the order needed to get my ordering correct. So while most of the time it is beneficial being able to use assumed sort in Alteryx if you are relying on a particular order you can't! So that resulted in the second part taking much longer than the first!

NicoleJohnson

Solved for stars and then played tool golf to get it down to this combination... Though I'm a bit disappointed in myself now that I see @bflick bringing back y=mx+b. Missed out on an opportunity to finally use that particular tidbit of knowledge! 😂

Spoiler

Cheers!

AkimasaKajitani

I use only one Generate Row tool to make diagonal line. It is a pretty forceful way. But it took long time to make the condition expression.

Spoiler

GitHub

https://github.com/AkimasaKajitani/AdventOfCode

estherb47

Wow, taking me back to HS math.

abs(ATAN2([y1]-[y2], [x1]-[x2]))*180/3.14 (to find 45 degree diagonal lines)

y=mx+b

My solution resembles @bflick 's solution

Spoiler

grossal

Very straight forward this time. Could have simplified the first one, but I'll need breakfast first.

Spoiler

dsmdavid

Spoiler

Thought this could be a good fun for spatial or golf. Went with golf...

https://github.com/dsmdavid/AdventCode2021

patrick_digan

Spoiler

cgoodman

@grossal 👏 going the extra step to use a count records instead of being lazy and using browse anywhere to get the total records.

danilang

Lulling us into a false sense of security with a relatively easy one on Day 5!

And I've forgotten even if I went to high school, let alone any math I may have done there!

Spoiler

The delta on the diagonals is always +/- 1 along both axes. Once you generate the points along one axis, you can use a multi-row(one of my favorite tools) to number the points and use the point number to calculate the offset from the start along the other.

Edit: I guess I did go to high school and something stuck since I used the word "delta" in the spoiler

Dan

Day 5.yxmd

Aguisande

I have to pass today, I couldn't understand the problem.

afv2688

Nice one for today 🙂

Spoiler

leozhang2work

Spoiler

Realise using straight line formula will probably made it easier. Since direction doesn't seem to matter, sort from low value to higher value may simplify things as well.

joshbennett

Have you ever found yourself making a macro for 15-20 minutes on auto-pilot before you realize you don't need a macro? Huh? Oh yeah, me neither...

Ugh, I struggled a bit initially with part 2 until my wife (who teaches math/science) was gracious enough to re-teach me y=mx+b (which she was quite excited to see make an appearance "out in the wild", let me tell you). After thinking about it through this lens, it was frustratingly simple.

Spoiler

aoc_2021_05_jbennett010.yxzp

SeanAdams

My solution is very similar to @afv2688 and @patrick_digan

(oh, and I'm using a few of the shared macros that folk have posted like the downloader and the switcher - thank you!)

Spoiler

- First split out the data into unique X&Y values using a regex
- Then split this into rows which are horizontal (constant Y) vs. any other line
- For the horizontal lines - iterate over Y since X does not vary - for example, the line Y=3
- For all other lines - iterate over X using the formula Y = mX + C. m is found using the (Y2-Y1)/(X2-X1) gradient function; and then c can be found by substituting any known X,Y combination into the formula above once m is known

- Once you've created all the points - you then just need to count how many times any given point occurs - so Part 1 is identical to part 2, but part 1 just excludes diagonals.

Part2.yxzp

caitlynmcintyre

From now on I'm building something that works with the example data, then plugging in my data. Saves so much time.

Spoiler

I'm sure there's a more mathematically sound way to do this but it works!

Mchappell67

I guess I took more of a brute-force approach; similar to other solutions, but didn't use y=mx+b (been WAY too long since school).

Oh, well - got the right answers...

Mark

advent5.yxmd

Quick Links

This months top contributors

atcodedog05 19458

Qiu 15866

binu_acs 15708

MarqueeCrew 13708

apathetichell 13703