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67 lines
1.9 KiB
67 lines
1.9 KiB
package day2
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import java.io.File
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object Day2 {
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fun sumOfCompatibleGames(hand: Hand) = readGames()
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.filter { it.isCompatibleWith(hand) }
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.map(Game::id)
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.sum()
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private fun readGames(): List<Game> =
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File("src/main/resources/day2/input.txt")
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.readLines()
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.map(Game.Companion::parse)
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}
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data class Game(val id: Int, val hands: List<Hand>) {
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fun isCompatibleWith(hand: Hand) =
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hand.fitsIn(
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hands.fold(Hand(0, 0, 0)) { currentMax: Hand, next: Hand ->
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Hand(
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maxOf(currentMax.red, next.red),
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maxOf(currentMax.green, next.green),
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maxOf(currentMax.blue, next.blue)
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)
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})
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companion object {
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/**
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* Example string: "Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green"
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*/
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fun parse(string: String) = string
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.split(':')
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.let {
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Game(
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id = NUMBER_REGEX.find(it[0])!!.value.toInt(),
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hands = it[1].split(';').map { Hand.parse(it) })
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}
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private val NUMBER_REGEX = Regex("\\d")
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}
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}
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data class Hand(val red: Int, val green: Int, val blue: Int) {
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fun fitsIn(other: Hand) = red >= other.red && green >= other.green && blue >= other.blue
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companion object {
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/**
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* Example string: "3 blue, 4 red"
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*/
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fun parse(string: String): Hand =
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Hand(
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RED_REGEX.find(string)?.groupValues?.get(1)?.toInt() ?: 0,
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GREEN_REGEX.find(string)?.groupValues?.get(1)?.toInt() ?: 0,
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BLUE_REGEX.find(string)?.groupValues?.get(1)?.toInt() ?: 0
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)
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private val RED_REGEX = Regex("""(\d+)\s+red""")
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private val GREEN_REGEX = Regex("""(\d+)\s+green""")
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private val BLUE_REGEX = Regex("""(\d+)\s+blue""")
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}
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}
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