Challenge #61: Save the Astronaut

The answer to last week's challenge can be found HERE.

In the novel, “The Martian”, astronaut Mark Watney is stranded on Mars. After getting a rover that transmits video back to earth, Watney communicates with mission control by setting up cards on sticks surrounding the rover – knowing the rover can rotate the camera 360 degrees. His method would be to show the rover camera a question, then record the letters that the mission control then points the rover camera at to assemble a response. However, knowing that there are 26 letters in the English alphabet, he realizes that the letters surrounding the rover would only be separated by 13 degrees – making it more difficult to understand what the rover is pointing at. As a solution, he then decides to set up the surrounding cards using the hexadecimal characters 0-9, A-F (16 cards + 1 card serving as the question). If the question card is sitting at 0 degrees and the 16 other letters (0-9, A-F) are ordered around the rover, the camera can only pan at 4 degrees per second, how long will it take for the rover to return the following message: “We are sending another mission. It will take 42 months.”?

Note: Assume the camera starts on the question card and ends on the last letter.

challenge_61_start_file.yxmd

challenge_61_solution.yxmd

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MarqueeCrew

@JoeM,

With the cards setup at equal distances around the rover, I have a question about the capability of the rover to pan left and right. If the rover only pans right, then the distance from 10 degrees to 0 degrees is 350. If it can go left, the distance is 10 degrees. What assumption can you share or should we figure that out for ourselves?

Cheers,
Mark

Max06270

If you wanna see the scene from the movie: https://www.youtube.com/watch?v=ffB0Je-xjKg

@JoeM I cannot find the exact same result, somehow my camera is 9 seconds slower than yours .

Assumptions:

Spoiler

I made the assumption that the camera takes always the shortest path and that it has to stop 1 sec on each card for Mark to take notes, but not sure if you did the same...

Solution:

Spoiler

challenge_61_MK.yxmd

MarqueeCrew

@Max06270,

I watched the clip (twice) and noticed that they didn't include punctuation in the text. Did you?

I don't want to look inside of the spoiler tags.

alex

Assumptions in my solution are as follows inside spoiler tag

Spoiler

1)camera pans in the direction that would travel the least amount of degrees

2) camera would have to go back to 0 degrees if a there is a duplicate card in succession

3) kept the first period, but deleted the last period. Also kept space

4) kept capitalization as is

5) used a formula to convert text to hex instead of the table

6) to minimize transmission time (and power supply) I did not add any start or end of transmission hex characters

I'm still 16 seconds off

Spoiler

Martian-AC.yxmd

MarqueeCrew

@JoeM

I have posted my solution.

After finishing mine, I compared our results and we're matching. I got there in a more convoluted way than you did.

Spoiler

I pictured each card as 1/2 of a set of cards required to produce the hex value. Given any 2 card combinations, I setup a table of the distance (degrees) between the two cards. Then I calculated the cards needed for each portion of the message and did a lookup. Visually, this made sense to me. Looking at your solution, it was more elegant.

So after writing code and using the API to NASA for Code calculations.... (just kidding)

Well played @Max06270 & @alex

challenge_61_MarqueeCrew.yxmd

Natasha

Here is my solution. I am pretty close, but also can't get the exact number of seconds.

At first I was way off, but then used @Max06270 assumption that the camera stops one second at each card, which makes sense, and my camera become 9 sec slower.

If I read the task carefully, the last sentence says " Note: Assume the camera starts on the question card and ends on the last letter."

Removing the last dot made my camera 25 sec faster.

Spoiler

challenge_61_NK.yxmd

JoeM

This week's solution has been posted. It's great to see all the different assumptions being called out - even some I had failed to take into account (re: stopping camera on each letter being a big one). Hope you had fun trying to think your way through that one!

PaulRB

Here is my solution. Thanks for converting the start file for 10.5 compatibility.

Now the interesting part: how does my solution compare to the model answer & others posted here.

challenge_61_solution.yxmd

mceleavey

What a fantastic challenge.

First, my assumptions are as follows:

1. The message is to be recreated exactly quoted, included cases and all punctuation in the quotes;

2. The camera must pause for one second on all cards, including an additional second pause on a sequentially repeated character (and not using @alex 's masochistic return to 0!) and counting one second for the final card;

3. The camera moves in the direction constituting the shortest distance.

Spoiler

First of all, my results are as follows:
1. With the one second pause on each card:

Results with delay.PNG

2. Without pause:
Results without delay.PNG

3. With a one second pause only for sequentially repeated characters:
Results with delay only for repeated characters.PNG

This is a little complex to break down, so it's easier to just have a look at the solution attached.

I get the same results as the posted solution up to a certain point, and that is the calculation of the camera degree. I've checked mine, and it starts to vary at row 59. I've checked my results manually and I get the same answer, so I don't know who has the correct calculation here, feel free to point out my mistake, however I see when there is a move from one character to another and back, I would assume those two movements would be the same distance which they are in my results but differ in the posted method. Again, I'm probably wrong, so please let me know!

challenge_61_solution.yxmd

estherb47

Most challenging so far for me. Nothing new here.

challenge_61-2_EHB_solution.yxmd

NicoleJohnson

My solution. Loved this one! Partially because I would definitely save Matt Damon...

Assumptions:

Remove spaces & characters. In life or death Mars rescue missions, proper punctuation is probably not necessary... I did leave the capital letters, however, as markers of a new "sentence" within the message.
Adopted the "wait for 1 second at each card you stop at" philosophy proposed by others.
Opted to go around in a full revolution if a card was repeated twice in a row, so that it was clear it was a new card.
Solved two ways - once for a Rover that moves only in one direction (clockwise, same direction as the 0-9 A-F cards are laid out), and once for a Rover that could switch direction between cards (choosing shortest distance to the next card).

Spoiler

challenge_61_start_file.yxmd

LordNeilLord

Assumptions

Spoiler

-The camera takes the shortest difference between cards
-The camera pauses for 2 seconds on duplicate characters
-All characters and punctuation included

I was 11 seconds quicker than the provided answer, so win win for Mark Watney

Solution

Spoiler

This has to be one of my favourite challenges to date...more like this please @JoeM

challenge_61_LNL.yxmd

J_white

Man! I'm glad I found this one as my first ever Alteryx Challenge. This was a lot of fun! I got 30minutes, but I didn't follow all of the rules, b/c we are on MARS! I didn't have time for spaces and punctuation.. But this could easily be redrawn to include punctuation and replace spaces with a proper identifier.

Spoiler

challenge_61_start_file.yxmd

vishalgupta

challenge_61_Vishal.yxmd

nick_ceneviva

Solution is attached. Assumes the camera can go in either direction.

challenge_61_Ceneviva.yxmd

lminors

Really enjoyed this one, with the context and everything. Great film and the books on the reading list! I used this as a problem solving exercise at Keyrus UK so hoping there will be some more solutions from colleagues submitted soon.

I tested it with upper case, lower case and title case and the title case was 4 minutes quicker so we'll go with that! My solution is attached below workflow in the spoiler:

Spoiler

Thanks,

Luke - Keyrus UK

WC61_LM_solution.yxmd

patrick_digan

Spoiler

challenge_61_start_file.yxmd

dsmdavid

Solved! As mentioned earlier, we are saving Mark & NASA some seconds by making sure the camera follows the shortest path to the next card (has to be less than 180, else go in the other direction) so this step in the original soluction is a tad shorter:

Spoiler

We can reduce 190.58...to ~170...

CharacterID	Order	Symbol	Cards	Card Position	Camera_Turn	Direction
30	59	n	6	148.235294117647	190.588235294118	left

solved#61.yxmd

samN

I think this was the most fun challenge yet!

Spoiler

Here are some assumptions I made.
The camera can turn both ways and chooses the faster of the two.
Stop for a second on each sign.
If there are repeating cards the camera will pause for 5 seconds for each additional duplicate. so if two are the same it will land on the card and then pause for 5 seconds and then move on.
The Camera does not have to return to the start
Assume that we group two cards to make a 4 bit hex number to be converted into a symbol.

My answer was different than the solution by less than a minute so I'm guessing it was probably due to some of these assumptions and perhaps i didn't make enough assumptions.
Awesome Challenge

challenge_61_samN.yxmd

ggruccio

Wow! That was fun! Watching the video clip from the movie helped a lot!

challenge_61_gg_finish.yxzp

philipmannering

This was a fun one. Everyone seems to have slightly different answers depending on assumptions. I assume shortest distance taken and no pause (which I accept would make it difficult to interpret). Solution attached.

Spoiler

challenge_61 - Save Matt Damon.yxmd

jasperlch

Solution attached.

challenge_61_JL.yxmd

JosephSerpis

Challenge Completed

Challenge_61_Joe_Serpis.yxmd

jamielaird

This was great fun. Here's my solution - just a smidge under 40 minutes assuming a 1 second dwell time on each card and no final period. I'm making the assumption that longer dwell time for duplicate cards will be interpreted as multiple instances of that card.

EDIT - is it just me, or does anyone else find splitting a string to rows *incredibly* satisfying? It's such a simple thing, but it gets me every time.

Spoiler

challenge_61_JL.yxzp

kelly_gilbert

Pretty fun! My solution doesn't match the given solution due to one assumption (see detail in spoiler). Otherwise, my workflow is pretty similar to the given solution.

Spoiler

Note, my solution assumes the camera can make a complete rotation (i.e. through zero), so my result is slightly lower because it takes the most efficient path available.

The given solution assumes that the camera cannot make a complete rotation (e.g. rotating from 339 degrees, clockwise through zero, to 148 degrees = 21+148 = 169 degrees). In this case, the solution would take the longer route, counterclockwise, from 339 to 148 (passing the 180-degree point) = 191 degrees.

This occurs in the word "moon", since "on" = hex 6F6E.
When moving from the F (338.82 degrees) to 6 (148.23 degrees), the shortest path would be to rotate clockwise, from 338 --> past 0 --> 148 = 169.41 degrees.

The solution takes the longer way around (counterclockwise, from 338 --> past 180 --> 148 = 190.59 degrees).

challenge_61_solution_klg.yxmd

kat

I let my camera go around in circles, back and forwards, which allowed it to be a little quicker. I tried to make it slower by adding end of transmission and moving it back to the last letter (that's how I understood that part). So interesting to see what different assumptions everyone makes

Spoiler

Challenge #61.yxmd

danilang

I assumed that the camera can pan both directions and paused for 1 second for each card.

Spoiler

i built a time between letters table and joined to the hex characters of the message assuming they started on the question.

Solution 61.png

Dan

challenge_61_solution_DL.yxmd

CHarrison

Challenge 61.yxmd

KOBoyle

Solution attached. I calculated the shortest path to the next card. After reading others comments, I too went back and added a 1 second pause.

Spoiler

Gauthier_B

I got pretty close but could not manage to match your result.

I went on assuming that the rover could pan left or right based on the shorter distance.

Gonna have a look at the solution now

challenge_61_start_file.yxmd

OldDogNewTricks

My solution is attached.

challenge_61_completed.yxmd

ch12345

I made a fundamental error in my processing: assuming that the message was never the target of the camera (so missing it from the 360 degree camera view, meaning that each letter was 22.5 degrees apart, simplifying finding the fastest route).

I also manually added in the start and end characters, although admittedly in the context they'd be fairly useless (unless you put a bell between 0 (message end) and 1 to indicate a new message had started).

Speculation aside, here is my inaccurate, and slower solution:

Spoiler

challenge_61_start_file CH.yxmd

JoBen

That was a lot of fun! Thanks for posting! Cheers!

challenge_61_Joben_Solution.yxmd

aiahwieder

Hm. My totals are still off by a little. There's a lot to assume here -- the time spent on each card, the direction of movement (uni- or bilateral?), whether repeated cards include movement between . . . I feel like I got pretty close, though!

challenge_61_solution.yxmd

lucia_haswell

My Solution:

Weekly_Challenge_61.yxmd

MilindG

Spoiler

Solution 61.yxmd

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