Add 2021 - Day 6 - Part 1

2021/06/input/1.txt

@@ -0,0 +1 @@
+1,3,4,1,1,1,1,1,1,1,1,2,2,1,4,2,4,1,1,1,1,1,5,4,1,1,2,1,1,1,1,4,1,1,1,4,4,1,1,1,1,1,1,1,2,4,1,3,1,1,2,1,2,1,1,4,1,1,1,4,3,1,3,1,5,1,1,3,4,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,5,2,5,5,3,2,1,5,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,5,1,1,1,1,5,1,1,1,1,1,4,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,3,1,2,4,1,5,5,1,1,5,3,4,4,4,1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,5,3,1,4,1,1,2,2,1,2,2,5,1,1,1,2,1,1,1,1,3,4,5,1,2,1,1,1,1,1,5,2,1,1,1,1,1,1,5,1,1,1,1,1,1,1,5,1,4,1,5,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,5,4,5,1,1,1,1,1,1,1,5,1,1,3,1,1,1,3,1,4,2,1,5,1,3,5,5,2,1,3,1,1,1,1,1,3,1,3,1,1,2,4,3,1,4,2,2,1,1,1,1,1,1,1,5,2,1,1,1,2

2021/06/main.kt

@@ -0,0 +1,44 @@
+import java.io.File
+import java.util.Collections
+
+fun main() {
+	val initialConfiguration = File("input/1.txt").readLines().single().split(',').map(String::toInt)
+	val configuration = FishConfiguration(initialConfiguration)
+	
+	for (day in 1..80) {
+		configuration.advanceToNextDay()
+		// configuration.print()
+	}
+	
+	println("Total fish: ${configuration.totalFish}")
+}
+
+class FishConfiguration(initialConfiguration: List<Int>) {
+	private val state = initialConfiguration.toMutableList()
+	private var day = 0
+	
+	val totalFish
+		get() = state.size
+	
+	fun advanceToNextDay() {
+		++day
+		
+		var newFish = 0
+		for ((index, timer) in state.withIndex()) {
+			if (timer == 0) {
+				++newFish
+				state[index] = 6
+			}
+			else {
+				state[index] = timer - 1
+			}
+		}
+		
+		state.addAll(Collections.nCopies(newFish, 8))
+	}
+	
+	@Suppress("unused")
+	fun print() {
+		println("Day ${day.toString().padStart(3)}: ${state.joinToString(",")}")
+	}
+}

README.md

@@ -35,3 +35,4 @@ The versions should not matter, but I used Visual Studio 2019 with `MSVC v142 (1
 | 2021 |  03 | Kotlin   |
 | 2021 |  04 | Kotlin   |
 | 2021 |  05 | Kotlin   |
+| 2021 |  06 | Kotlin   |

build.gradle.kts

@@ -48,4 +48,5 @@ sourceSets {
 	make(2021, 3)
 	make(2021, 4)
 	make(2021, 5)
+	make(2021, 6)
 }