Advent of Code - adventofcode.com

Messing around with indexes always trips me up, but I've got them both.

Was a quick one today.

https://gist.github.com/dmckennell/bcb6db60d0150bfc877b21492d4f0f78

...prints:

Solving puzzle for Day 2 (Year 2020)
Loading input from 2020/Day02.txt
Part 1 took 0.030277581 seconds
Part 2 took 0.021179534 seconds
Part 1: 528
Part 2: 497

https://github.com/TijmenK/AoC2020/blob/main/day2.py

Doing this for the first time this year - in js / node

Day 2 in perl: https://gist.github.com/alexgreenbank/28d1be51466e070115ea304882ffa354

What are you doing for importing the data? I really don't want to go through and edit 1000 lines of strings into an array of objects.

using fs.readFile and a separate textfile where I copied the input.
Did debate trying to fetch it directly from the server but then realised everyones input is different so I would need to deal with auth and I cba.

Yeah I've given up trying to be clever and just used find and replace to turn it into an array of strings

https://github.com/ips-james/AdventOfCode/blob/main/day2.py

410 passwords out of 1000 were valid for part 1
694 passwords out of 1000 were valid for part 2
0.18user 0.05system 0:00.11elapsed 212%CPU (0avgtext+0avgdata 39420maxresident)k
0inputs+64outputs (0major+11049minor)pagefaults 0swap

Code incredibly inelegant, and no tests. MUST.DO.BETTER :-)

And now it's my python version too.

Congratulations - you have now become my python tutor!

I did this in bash - because box of hammers, and I didn't want to suffer the ignominy of doing it in excel or vba.

#!/bin/bash
# Advent of Code - Day 1, Puzzle 1
inputfile=$1
# numbercount=$(cat $1 | wc -l) # Edit because numbers
numbercount=$(( $(cat $1 | wc -l) + 1 ))
start=$SECONDS
for ((i = 1 ; i < $numbercount ; i++)); do
    for ((j = $i + 1 ; j < $numbercount ; j++)); do
        ivalue=$(awk "NR == $i" $inputfile)
        jvalue=$(awk "NR == $j" $inputfile)
        if [[ $(( $ivalue + $jvalue )) -eq 2020 ]] ; then
            echo "$ivalue + $jvalue = $(( $ivalue + $jvalue )), $ivalue * $jvalue = $(( $ivalue * $jvalue ))" 
        fi
    done
done
duration=$(( SECONDS - start ))
echo $duration

 :: tiswas@laptop2:/home/tiswas/Temp :: 
 $ ./sum_to_2020.sh input1.txt 
1632 + 388 = 2020, 1632 * 388 = 633216
76 seconds 19900 records

Seeing working python code for this is useful though, as I'm learning that from scratch at the moment.

[Edit] because missing a number in the loop

Google Sheets Day 1:
https://docs.google.com/spreadsheets/d/1joA1oMsoGaDCwX0u8CAK7IUuMeFqyfLEYzzIWzGB1d0/edit#gid=0

Google Sheets Day 2:
https://docs.google.com/spreadsheets/d/17LXRC-kEewCl3K1mvA1dzWJE8geZx9bK78o2fClZc0g/edit?ouid=113006542528071116740&usp=sheets_home&ths=true

There's probably a neater way to count characters in a string than deleting them and comparing the length =len(B2)-len(SUBSTITUTE(B2,C2,"")) but it's not obvious what.

My java did that too.
I toyed with using a regex, but didn't

Done both, I got hung on the first one today a bit due to stupid copy and paste errors. Can share vanilla JS answers if anyone needs help

Every day's a school day - learned about arrays in bash.

#!/bin/bash
start=$SECONDS
inputfile=$1
mapfile -t < $inputfile

# Part 1 - 2 numbers
for i in "${MAPFILE[@]}"; do
    mycount=$(( mycount + 1 ))
    if [[ " ${MAPFILE[@]} " =~ " $(( 2020 - $i )) " ]] ; then
        echo "$i, $(( 2020 -$i)), $(( $i * (2020 - $i)))"
        duration=$(( SECONDS - start ))
        echo "$duration seconds $mycount records"
        break
    fi
done


# Part 2 - 3 numbers
mycount=0
start=$seconds
for i in "${MAPFILE[@]}"; do
    for j in "${MAPFILE[@]}"; do
        mycount=$(( mycount + 1 ))
        if [[ " ${MAPFILE[@]} " =~ " $(( 2020 - $i -$j )) " ]] ; then
            echo "$i, $j, $(( 2020 -$i - $j )), $(( $i * $j * (2020 - $i - $j) ))"
            duration=$(( SECONDS - start ))
            echo "$duration seconds $mycount records"
            exit
        fi
    done
done

 $ ./array_test.sh input1.txt 
1632, 388, 633216
0 seconds 82 records
1607, 196, 217, 68348924
3 seconds 14573 records

Anyone else doing this is Haskell? I'm pretty new to it and had to fight my way through the first two days!

Another delay to submitting part 2 because I SIMPLY DID NOT READ THE WORDING.

When will I learn.

Not this year (as I want to focus on just getting to the end of the advent this time), but I'd like to see your solutions as you go as I'm curious!

Have seen a few GitHub projects with some Haskell advent GitHub projects with file reading scaffolding in place, so will likely clone one of those before next year's challenge.

The best prep is going back and completing previous years, gives you a good idea of what scaffolding may be useful.

Reading in maps into arrays (like today) is a common theme.

(I don't bother with any pre-written code or scaffolding but I will go and copy/paste from previous submissions if I realise there's a useful chunk of time that could be saved.)

If this year is like any of the previous ones they'll be some form of a pseudo computer that you need to implement that will come back again and again (and slowly be built up), so there will be some reuse built in.

Another eminently spreadsheetable one:
https://docs.google.com/spreadsheets/d/17_5yPJ8oNENFlRtqBnbCOLqE50RDK5QlLC_3p1v8Csg/edit?usp=sharing

First three days in Python

https://gist.github.com/wence-/7d2a722fba29c94149a75beebfd5333c

Will try and update as I go. Thought about using the opportunity to teach myself Rust, but that will wait.

I'm usually put off by these "visual" challenges but stuck with it this time. Made a few mistakes with the indexing, offsets and getting my rows and columns mixed up but got there in the end.

Python: https://gitlab.com/-/snippets/2046058

TIL about enumerate!

404 on link (private visibility?)

I have an idea how to do this in JS but it's not going to be pretty.