Advent of Code Leaderboard 2023 / Day 5

Submit solution

Rules

You're welcome to participate alone or in a team.
You may submit multiple solutions and explore different programming languages.
Stick to the standard library of your language, no further dependencies/libraries, except the ones which OneCompiler provides (e.g. NumPy for Python).
Ensure your code aligns to the template (Python, Rust, Go, Kotlin, JavaScript, C#, TypeScript, C++, Java, C, Swift, Scala, Ruby), reading the puzzle input from stdin (terminated with end-of-file), and printing the solution to stdout.
Please refrain from making network requests, reading data from files, or storing data in variable/function/class names for reflection.

Code publicly visible

Leaderboard

	Name	Language	Tokens Sum	Tokens Part 1	Tokens Part 2	Last change
1	Valentin Slawicek	Kotlin	1036	408	628	7 months ago

628 tokens in Kotlin for part 2 by Valentin Slawicek

Download solution

dataclassMapEntry(
valsource:String,
valdestination:String,
valsourceStart:Long,
valdestinationStart:Long,
valrangeLength:Long
){
valsourceRange=LongRange(sourceStart,sourceStart+rangeLength-1)
}
funmain(){
valmapEntries=mutableListOf<MapEntry>()

varseeds:List<LongRange>=emptyList()

varcurrentMap=""to""// Start to end

generateSequence(::readLine)
.forEach{line->
when{
line.startsWith("seeds: ")->{
seeds=line.substringAfter("seeds: ")
.split(" ")
.map{it.toLong()}
.chunked(2)
.map{LongRange(it[0],it[0]+it[1]-1)}
}

line.endsWith(" map:")->{
currentMap=line.substringBefore("-")toline.substringAfter("-to-").substringBefore(" ")
}

line.isEmpty()->Unit// Skip
else->{
valmapEntryString=line.split(" ").map{it.toLong()}
mapEntries+=MapEntry(
source=currentMap.first,
destination=currentMap.second,
destinationStart=mapEntryString[0],
sourceStart=mapEntryString[1],
rangeLength=mapEntryString[2]
)
}
}
}

funLongRange.intersect(other:LongRange):LongRange{
returnLongRange(maxOf(this.first,other.first),minOf(this.last,other.last))
}

fungetMapEntries(source:String,range:LongRange):Map<MapEntry,LongRange>{
valrelevantMapEntries=mapEntries.filter{it.source==source}.sortedBy{it.sourceStart}
valtargetMapEntries=relevantMapEntries.toMutableList()
varlastEnd=-1L
relevantMapEntries.forEach{mapEntry->
if(mapEntry.sourceStart!=lastEnd+1){
// Add unmapped gap
targetMapEntries+=relevantMapEntries.first().copy(
sourceStart=lastEnd+1,
destinationStart=lastEnd+1,
rangeLength=mapEntry.sourceStart-lastEnd
)
}
lastEnd=mapEntry.sourceRange.last
}
// Add last unmapped (until Long.MAX_VALUE)
targetMapEntries+=relevantMapEntries.first()
.copy(sourceStart=lastEnd+1,destinationStart=lastEnd+1,rangeLength=Long.MAX_VALUE-lastEnd)

returntargetMapEntries.filter{!it.sourceRange.intersect(range).isEmpty()}
.associateWith{mapEntry->
valoffset=mapEntry.destinationStart-mapEntry.sourceStart
valsourceIntersectedRange=mapEntry.sourceRange.intersect(range)
LongRange(sourceIntersectedRange.first+offset,sourceIntersectedRange.last+offset)
}
}

funresolve(source:String,range:LongRange):List<LongRange>{
valresolvedMapEntries=getMapEntries(source,range)
returnresolvedMapEntries.flatMap{(mapEntry,range)->
if(resolvedMapEntries.keys.first().destination=="location"){
listOf(range)
}else{
resolve(mapEntry.destination,range)
}
}
}

println(seeds.minOf{seed->resolve("seed",seed).minBy{it.first}.first})
}