https://kotlinlang.org logo
Docs
Join the conversationJoin Slack
Channels
100daysofcode
100daysofkotlin
100daysofkotlin-2021
advent-of-code
aem
ai
alexa
algeria
algolialibraries
amsterdam
android
android-architecture
android-databinding
android-studio
androidgithubprojects
androidthings
androidx
androidx-xprocessing
anime
anko
announcements
apollo-kotlin
appintro
arabic
argentina
arkenv
arksemdevteam
armenia
arrow
arrow-contributors
arrow-meta
ass
atlanta
atm17
atrium
austin
australia
austria
awesome-kotlin
ballast
bangladesh
barcelona
bayarea
bazel
beepiz-libraries
belgium
berlin
big-data
books
boston
brazil
brikk
budapest
build
build-tools
bulgaria
bydgoszcz
cambodia
canada
carrat
carrat-dev
carrat-feed
chicago
chile
china
chucker
cincinnati-user-group
cli
clikt
cloudfoundry
cn
cobalt
code-coverage
codeforces
codemash-precompiler
codereview
codingame
codingconventions
coimbatore
collaborations
colombia
colorado
communities
competitive-programming
competitivecoding
compiler
compose
compose-android
compose-desktop
compose-hiring
compose-ios
compose-mp
compose-ui-showcase
compose-wear
compose-web
connect-audit-events
corda
cork
coroutines
couchbase
coursera
croatia
cryptography
cscenter-course-2016
cucumber-bdd
cyprus
czech
dagger
data2viz
databinding
datascience
dckotlin
debugging
decompose
decouple
denmark
deprecated
detekt
detekt-hint
dev-core
dfw
docs-revamped
dokka
domain-driven-design
doodle
dsl
dublin
dutch
eap
eclipse
ecuador
edinburgh
education
effective-kotlin
effectivekotlin
emacs
embedded-kotlin
estatik
event21-community-content
events
exposed
failgood
fb-internal-demo
feed
firebase
flow
fluid-libraries
forkhandles
forum
fosdem
fp-in-kotlin
framework-elide
freenode
french
fritz2
fuchsia
functional
funktionale
gamedev
ge-kotlin
general-advice
georgia
geospatial
german-lang
getting-started
github-workflows-kt
glance
godot-kotlin
google-io
gradle
graphic
graphkool
graphql
graphql-kotlin
graviton-browser
greece
grpc
gsoc
gui
hackathons
hacktoberfest
hamburg
hamkrest
helios
helsinki
hexagon
hibernate
hikari-cp
hire-me
hiring
hongkong
hoplite
http4k
hungary
hyderabad
image-processing
india
indonesia
inkremental
intellij
intellij-plugins
intellij-tricks
internships
introduce-yourself
io
ios
iran
israel
istanbulcoders
italian
jackson-kotlin
jadx
japanese
jasync-sql
java-to-kotlin-refactoring
javadevelopers
javafx
javalin
javascript
jdbi
jhipster-kotlin
jobsworldwide
jpa
jshdq
juul-libraries
jvm-ir-backend-feedback
jxadapter
k2-early-adopters
kaal
kafka
kakao
kalasim
kapt
karachi
karg
karlsruhe
kash_shell
kaskade
kbuild
kdbc
kgen-doc-tools
kgraphql
kinta
klaxon
klock
kloudformation
kmdc
kmm-español
kmongo
knbt
knote
koalaql
koans
kobalt
kobweb
kodein
kodex
kohesive
koin
koin-dev
komapper
kondor-json
kong
kontent
kontributors
korau
korean
korge
korim
korio
korlibs
korte
kotest
kotest-contributors
kotless
kotlick
kotlin-asia
kotlin-beam
kotlin-by-example
kotlin-csv
kotlin-data-storage
kotlin-foundation
kotlin-fuel
kotlin-in-action
kotlin-inject
kotlin-latam
kotlin-logging
kotlin-multiplatform-contest
kotlin-mumbai
kotlin-native
kotlin-pakistan
kotlin-plugin
kotlin-pune
kotlin-roadmap
kotlin-samples
kotlin-sap
kotlin-serbia
kotlin-spark
kotlin-szeged
kotlin-website
kotlinacademy
kotlinbot
kotlinconf
kotlindl
kotlinforbeginners
kotlingforbeginners
kotlinlondon
kotlinmad
kotlinprogrammers
kotlinsu
kotlintest
kotlintest-devs
kotlintlv
kotlinultimatechallenge
kotlinx-datetime
kotlinx-files
kotlinx-html
kotrix
kotson
kovenant
kprompt
kraph
krawler
kroto-plus
ksp
ktcc
ktfmt
ktlint
ktor
ktp
kubed
kug-leads
kug-torino
kvision
kweb
lambdaworld_cadiz
lanark
language-evolution
language-proposals
latvia
leakcanary
leedskotlinusergroup
lets-have-fun
libgdx
libkgd
library-development
linkeddata
lithuania
london
losangeles
lottie
love
lychee
macedonia
machinelearningbawas
madrid
malaysia
mathematics
meetkotlin
memes
meta
metro-detroit
mexico
miami
micronaut
minnesota
minutest
mirror
mockk
moko
moldova
monsterpuzzle
montreal
moonbean
morocco
motionlayout
mpapt
mu
multiplatform
mumbai
munich
mvikotlin
mvrx
myndocs-oauth2-server
naming
navigation-architecture-component
nepal
new-mexico
new-zealand
newname
nigeria
nodejs
norway
npm-publish
nyc
oceania
ohio-kotlin-users
oldenburg
oolong
opensource
orbit-mvi
osgi
otpisani
package-search
pakistan
panamá
pattern-matching
pbandk
pdx
peru
philippines
phoenix
pinoy
pocketgitclient
polish
popkorn
portugal
practical-functional-programming
proguard
prozis-android-backup
pyhsikal
python
python-contributors
quasar
random
re
react
reaktive
realm
realworldkotlin
reductor
reduks
redux
redux-kotlin
refactoring-to-kotlin
reflect
refreshversions
reports
result
rethink
revolver
rhein-main
rocksdb
romania
room
rpi-pico
rsocket
russian
russian_feed
russian-kotlinasfirst
rx
rxjava
san-diego
science
scotland
scrcast
scrimage
script
scripting
seattle
serialization
server
sg-user-group
singapore
skia-wasm-interop-temp
skrape-it
slovak
snake
sofl-user-group
southafrica
spacemacs
spain
spanish
speaking
spek
spin
splitties
spotify-mobius
spring
spring-security
squarelibraries
stackoverflow
stacks
stayhungrystayfoolish
stdlib
stlouis
strife-discord-lib
strikt
students
stuttgart
sudan
swagger-gradle-codegen
swarm
sweden
swing
swiss-user-group
switzerland
talking-kotlin
tallinn
tampa
teamcity
tegal
tempe
tensorflow
terminal
test
testing
testtestest
texas
tgbotapi
thailand
tornadofx
touchlab-tools
training
tricity-kotlin-user-group
trójmiasto
truth
tunisia
turkey
turkiye
twitter-feed
uae
udacityindia
uk
ukrainian
uniflow
unkonf
uruguay
utah
uuid
vancouver
vankotlin
vertx
videos
vienna
vietnam
vim
vkug
vuejs
web-mpp
webassembly
webrtc
wimix_sentry
wwdc
zircon
Powered by Linen
advent-of-code
  • n

    Nir

    12/12/2020, 1:49 PM
    today's puzzle really makes me want proper sum types, sealed classes aren't cutting it. You can't put an enum class inside a sealed class because it can't inherit 😞
    i
    e
    • 3
    • 5
  • b

    bjonnh

    12/13/2020, 4:13 AM
    🎉*Day 13 solution thread*😈
    m
    j
    +3
    • 6
    • 11
  • b

    bjonnh

    12/13/2020, 5:28 AM
    want to see how I did i t?
    n
    e
    • 3
    • 23
  • b

    bjonnh

    12/13/2020, 5:29 AM
    I'm stuck on computation on part2, it is way too slow
    m
    i
    +3
    • 6
    • 34
  • b

    bjonnh

    12/14/2020, 4:32 AM
    👾*Day 14 solution thread*:kotlin:
    a
    n
    +4
    • 7
    • 92
  • a

    adamratzman

    12/15/2020, 4:55 AM
    Day 15 solution thread :kotlin-intensifies:
    d
    a
    +6
    • 9
    • 154
  • k

    kartikpatodi

    12/15/2020, 1:07 PM
    Help needed for day 14 ‼️
    t
    • 2
    • 8
  • a

    adamratzman

    12/16/2020, 4:56 AM
    Day 16 solution thread :kotlin-gradient:
    j
    a
    +4
    • 7
    • 110
  • b

    bjonnh

    12/17/2020, 2:50 AM
    💥Day 17 solution thread🧠
    n
    d
    +5
    • 8
    • 121
  • b

    bjonnh

    12/17/2020, 9:21 PM
    why does x=0, y=0, z=0 switches to active after their first cycle? what are its 3 neighbors?
    j
    • 2
    • 7
  • k

    Kroppeb

    12/18/2020, 5:32 AM
    Day 18 solution thread
    m
    e
    +4
    • 7
    • 56
  • k

    Kroppeb

    12/18/2020, 5:34 AM
    For those wondering how most of the people on the leaderboard are so fast. Those are all scripting languages (ruby and python) which replaced the operators with a different one with the impl of the intended operator, and then evaled the line
    i
    e
    • 3
    • 2
  • n

    Nir

    12/18/2020, 7:04 PM
    Random style question:
    line.mapIndexedNotNull{ y, c -> if(c == '#') (x to y).toPoint(d) else null }
    Or:
    line.withIndex().filter { it.value == '#' }.map { (y, _) -> (x to y).toPoint(d) }
    e
    k
    b
    • 4
    • 14
  • a

    andyb

    12/19/2020, 9:17 AM
    Day 19 solution thread
    e
    n
    +3
    • 6
    • 29
  • b

    bjonnh

    12/20/2020, 4:55 AM
    🎄Day 20 solution thread⏳
    j
    a
    +7
    • 10
    • 60
  • d

    David Whittaker

    12/21/2020, 5:57 AM
    🎅 Day 21 solutions discussion
    a
    e
    +4
    • 7
    • 25
  • a

    andyb

    12/22/2020, 8:33 AM
    🎄 Day 22 : Solutions Thread
    f
    n
    +4
    • 7
    • 74
  • a

    andyb

    12/23/2020, 10:49 AM
    🎄 Day 23 : Solutions Thread
    e
    j
    +4
    • 7
    • 25
  • a

    andyb

    12/24/2020, 10:05 AM
    🎅 Day 24 : Solutions Thread
    j
    k
    +6
    • 9
    • 76
  • e

    ephemient

    12/25/2020, 1:45 PM
    🎁 Day 25: Solutions Thread
    t
    n
    +2
    • 5
    • 14
  • b

    bjonnh

    01/14/2021, 4:10 AM
    Hey @todd.ginsberg you should advertise your talk
    j
    t
    +2
    • 5
    • 24
  • b

    bjonnh

    03/19/2021, 7:59 PM
    32 it seems: println((0.."100000001".toInt(2)).count { it.toString(2).let { it == it.reversed() } })
    ➕ 1
    👌 2
    m
    e
    • 3
    • 9
  • j

    Jakub Chrzanowski

    11/29/2021, 10:11 PM
    Hey folks! This year, as @Sebastian Aigner mentioned in the above blog post/video, we’re providing a GitHub Template Repository to let you quickly create an Advent of Code project within your GitHub account. Long story short, it’s available here with a README explaining what’s going on (FYI, there’ll be a giveaway going on). I’m also writing this note to ask you for a favor – I’ll be happy with any feedback before the actual contest begins so I can provide relevant patches right before. Thanks!
    🆒 1
    e
    • 2
    • 4
  • u

    user

    11/30/2021, 5:00 AM
    2^0 days until Advent of Code!
    😄 2
    :kotlin-intensifies: 6
    d
    g
    • 2
    • 2
  • j

    Jakub Gwóźdź

    11/30/2021, 1:24 PM
    any guesses which day this year will be about Chinese reminder theorem? 🙂
    :blob-nervous: 1
    😅 1
    😂 1
    g
    e
    p
    • 4
    • 3
  • u

    user

    12/01/2021, 5:00 AM
    Advent of Code 2021 day 1 🧵
    k
    d
    +14
    • 16
    • 38
  • j

    Jakub Gwóźdź

    12/01/2021, 5:26 AM
    which leaderboard are we using this year?
    d
    k
    m
    • 4
    • 4
  • m

    Michael Böiers

    12/01/2021, 2:28 PM
    I’m wondering - some people are posting solutions without input parsing. IMHO that should be part of the solution. What do you think?
    m
    p
    +2
    • 5
    • 7
  • m

    Marcin Wisniowski

    12/01/2021, 3:32 PM
    Is it possible to get input data onto play.kotlinlang.org somehow? That would be a nice way to share runnable solutions.
    j
    m
    • 3
    • 13
  • m

    marcinmoskala

    12/01/2021, 9:26 PM
    Hey everyone, this year I am also publishing some Advent challenges. Here is the first week: https://kt.academy/article/advent-2021-week1
    p
    m
    • 3
    • 5
Powered by Linen
Title
m

marcinmoskala

12/01/2021, 9:26 PM
Hey everyone, this year I am also publishing some Advent challenges. Here is the first week: https://kt.academy/article/advent-2021-week1
p

Paul Woitaschek

12/01/2021, 10:29 PM
Fun challenge, thanks 🙂 https://gist.github.com/PaulWoitaschek/84cf08b07abc56e4c43a2b7ec0b43508
Ha, simpler solution: https://gist.github.com/PaulWoitaschek/6526ee2397e8d67fa56f5182a3aa492a
m

Matteo Mirk

12/02/2021, 8:41 AM
will try them, thanks!
m

marcinmoskala

12/02/2021, 10:35 PM
@Paul Woitaschek Looks great 🙂
Any idea for the second problem?
View count: 3