Did anyone else use reduce/`reduced`? It feels dirty but I can’t figure out how to get the same efficiency without it. My other solution was to use some but created the whole set of inputs before hand.

(defn find-ints-summing-to-target [coll]
  (reduce (fn [seen-set n]
            (let [diff (- target-sum n)]
              (if (seen-set diff)
                (reduced #{n diff})
                (conj seen-set n))))
          #{}
          coll))

it also returns the whole set if a pair isn’t found which is a terrible result in the negative find case

ah looks like skykanin did something similar above in a cleaner fashion

Today I just threw core.logic with finite domain at it, which worked out quite nice: https://github.com/IamDrowsy/aoc-2020/blob/master/clojure/src/advent_of_code/d01.clj

Day 2, not bad, most of the work was processing the input into usable form. E.g.

{:lb 1, :ub 3, :ch \a, :pw "abcde"}

(defn pwgood? [{:keys [lb ub ch pw]}]
  (<= lb (get (frequencies pw) ch 0) ub))

(defn pwgood2? [{:keys [lb ub ch pw]}]
  (= 1 (count (filter #(= ch %)
     [(nth pw (dec lb)) (nth pw (dec ub))]))))

I am curious what did you you use to parse data for Day 2. Have you used regexp or some nice parser combinator library?

My solution for day 2 https://youtu.be/rghUu4z5MdM

https://github.com/transducer/adventofcode/blob/master/src/adventofcode/2020/day2.clj

Has someone figured out a way to slurp the input data directly from the site? I’m lazy, so if someone has this solved in a nice module, I’d love to have it. 😃 I’m also not lazy, so if this is not done by someone, I might try to do it, if someone here does not tell me it is probably very hard. And I’m the sharing type. Haha.

There is some Python program somewhere

https://github.com/wimglenn/advent-of-code-data

aocd > input.txt  # saves today's data
aocd 13 2018 > day13.txt  # save some other day's data

If I end up rolling this, I’ll have use for that to see what is involved.

Was attempting to do so yesterday, then I realised authentication is required

lazy way I think would be doing it first from the browser, "copy as cURL" so that it has your cookie headers in there, then you can adjust that curl line to download the other ones as long as your session remains valid

In the Python aocd tool you can add the value of the session cookie in the AOC_SESSION env var or ~/.config/aocd/token file

Wow as always it’s fascinating to watch Clojurians solution in this channel. This year I’m using ReasonML(family of OCaml) since my company has chosen it. https://github.com/namenu/advent-of-reason/blob/master/src/Year2020/Year2020_Day01.res Yes, it’s typed, I miss Clojure so badly.

Maybe a program can login via the GitHub SSH key so that you don’t need the session

If you use GitHub to login

Not sure if that’s possible

@pez https://github.com/lambdaisland/aoc_2020/blob/main/bin/fetch_input

just need to find the session id with devtools and put a export AOC_SESSION=... in your shell profile

And in the same way, it's also pretty easy to get the input via clojure (I just store the session in a file) https://github.com/IamDrowsy/aoc-2020/blob/581097350d2dc7865304ffc9eddaf6a479406ca1/clojure/src/advent_of_code/util.clj#L9:L13

Decided to go the easy path that @plexus pointed out. Copy as cURL from the problem page when I start reading it-> Grab the session cookie there -> (set-fetch-cookie! "<cookie>") -> Hack away until I need the input -> (util/fetch-input <day>)

(ns pez.aoc2020.util
  (:require [clj-http.client :as client]))

(def ^:dynamic *fetch-cookie* "")

(defn set-fetch-cookie! [cookie]
  (alter-var-root #'*fetch-cookie* (constantly cookie)))

(defn fetch-input [day]
  (if (seq *fetch-cookie*)
    (try
      (:body (client/get
              (str "" day "/input")
              {:cookies {"session" {:value *fetch-cookie*}}}))
      (catch Exception e
        (println "Ho, ho, ho! Did you forget to `set-fetch-cookie!`?")
        (throw e)))
    (throw (Exception. "Ho, ho, ho! You forgot to `set-fetch-cookie!` first."))))

(comment
  (def input
    "1-3 a: abcde
1-3 b: cdefg
2-9 c: ccccccccc")
  (util/set-fetch-cookie! "retracted")
  (def input (util/fetch-input 2))
  (->> input
       (parse)
       (filter checks2?)
       (map :pwd)
       (count)))

nothing fancy but my day 02 solution https://github.com/listba/advent-of-code-2020/blob/master/clojure/src/aoc_2020/days/02.clj

my also not fancy day 2… I like how declarative it came out looking https://gist.github.com/KennyMonster/eb6ea22eaba1a1a1201820ef1bddc1cf

I put my input-slurper into a gist: https://gist.github.com/PEZ/bcd23b9bc099b8b21a41c8c9de78a0f4

hi there. Here is my day 1 "theorically fast" solution https://github.com/green-coder/advent-of-code-2020/blob/801ebdeb9afa3904c1a5e31aeb9386e30e950c78/src/aoc/day_1.clj#L34

this is probably more a #beginners question, but figured I’d ask here since it’s related to the Advent of Code stuff I’m trying why isn’t this working? I copied problem 1's input file to a file called input in resources (in a Leinengen app template project)

(slurp (io/resource "input"))