Advent of Code

[Greenbank]

(I have all 250 stars, be interesting to see the stats on how many people have done that. There were 362 people with 200 stars by April 2019: https://twitter.com/ericwastl/status/1116561274379259904 )

As of recently only 283 have all 250 stars:-

https://twitter.com/ericwastl/status/1213134461229031424

[Ashaman42]

Well I made a start at AoC 2019 in January to learn some new skills for work and to occupy slow spots at work. Got halfway through Day 3 and stalled somewhat - mostly due to work getting busy.

Well given the current lockdown and the fact I can't do much of my job from home I started again from scratch. I'm up to Day 5 now and plodding away. I don't really know how to program so it's a lot of Googling and head scratching. I'm pretty sure in days 1 - 3 I made exactly the same mistakes as I managed the first time round 

I'm also fairly sure that some of what I'm doing is completely the opposite of best practise but there we go. Definitely doing something wrong as each run of my day 3 solution with the full input takes well over an hour to chug through.

Currently programming in C++ via Visual Studio Community 2019.

[Greenbank]

Definitely doing something wrong as each run of my day 3 solution with the full input takes well over an hour to chug through.

If you can describe here in words how your algorithm works then someone here can give pointers...

[Ashaman42]

Cheers 

I'll probably take you up on that at some point. Probably not today as I'm hip deep in day 5 and I think I'm getting somewhere with it. May as well keep on when I'm on a roll 

[vorsprung]

Definitely doing something wrong as each run of my day 3 solution with the full input takes well over an hour to chug through.

If you can describe here in words how your algorithm works then someone here can give pointers...

given that he is coding in C++ pointers are the problem

[Davef]

If you get stuck I have all 49 solutions in  Microsoft c++ and can give some hints.

I also have some ludicrously large intcode programs.


Sent from my iPad using Tapatalk

[Greenbank]

Not long to go...I hope Eric has been busy.

[Ben T]

could do with it this month really

[Greenbank]

Tomorrow...

[R_nger]

Broken ?

"We'll be right back!"

[Greenbank]

I think the input generator is broken for some people.

Ah, he's posted over on reddit to say it was just his AWS instances running out of resources and shutting down. All due to the site being utterly swamped in the first few seconds after day 1 went live.

(I'm happy that happens at 5am UK time as I'm not interested in trying to get into the top 100.)

I got my input and was able to get both stars.

[Diver300]

Eric really has managed to set up the perfect conditions for an unintentional DDoS attack on his servers.

I thought that today's puzzle was a bit simple.

[Greenbank]

The first two or three days are usually very gentle.

There's still plenty of scope for different approaches to even this simple problem though, some more efficient than others.

(Mine runs nigh on instantaneously even when I tell it to look for more than 4 numbers that add to 2020 - there is a 4 number solution for my input - no solutions other numbers though.)

[grams]

I did mine in Google Sheets with Vlookup. Managed to bodge it to find the four number solution too.

It runs with much fan noise and beachballing, like all great programs.

[Ben T]

(click to show/hide)

select n1.num * n2.num * n3.num from Day1 n1, Day1 n2, Day1 n3 where n1.num >= n2.num and n2.num >= n3.num and n1.num+n2.num+n3.num = 2020

[Greenbank]

(click to show/hide)

Don't normally do them in python but decided to give it a go.

Final spoiler, only click here if you want to see the code: https://gist.github.com/alexgreenbank/55daaa31c84974e1971af2e40e207784

[Davef]

I am redoing it in nostalgic intcode.

[Davef]

http://cloud.tapatalk.com/s/5fc661d8a8566/day1.txt
If anyone wants to test their intcode computer from last year attached is this years day1 part 1 solution in intcode. It reads 200 lines from stdin and then produces the answer. It is large as it includes a pile of unneeded utility code.

[Pingu]

Day 1 done. Maybe I'll quit while I'm ahead.

[Greenbank]

Once again it pays to read the problem description, including the bit highlighted in bold.

[Ben T]

two lines of easily maintainable code 

(click to show/hide)

awk -F'[ :-]' 'NF { print $5"\t^[^"$3"]*("$3"[^"$3"]*){" $1","$2"}[^"$3"]*$" }' day2.txt | awk '{ if($1 ~ $2) print $1 }' | wc -l

awk -F'[ :-]' 'NF { print substr($5,$1,1) "\t" substr($5,$2,1) "\t" $3 }' day2.txt | awk 'NF { print sub($3,"",$1) + sub($3,"",$2) }' | grep 1 | wc -l

[grams]

Another victory for Google Sheets:
https://docs.google.com/spreadsheets/d/17LXRC-kEewCl3K1mvA1dzWJE8geZx9bK78o2fClZc0g

[freeflow]

Bah humbug.  Day2 with VBA using an interface and injected code!!!!!

[Greenbank]

Some ugly / semi-minimalist perl:-

(click to show/hide)

#!/usr/bin/perl

while( <> ) {
        @o = split( /\W+/ );
        %l=();
        map { $l{$_}++ } split( //, $o[3] );
        $r[0]++ if( $l{$o[2]} >= $o[0] && $l{$o[2]} <= $o[1] );
        $r[1]++ if( substr( $o[3], $o[0]-1, 1 ) eq $o[2] xor substr( $o[3], $o[1]-1, 1 ) eq $o[2] );
}
print "@r\n";

(I know it can be code golfed to a lot less than that, but that's about as minimalist as I'd go before it starts to become a puzzle rather than recognisable code.)

[Pingu]

Day 2 done  I'm not brave enough to share my crappy JS coding though