day 10

src/main/kotlin/me/gergo/Aoc10.kt

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+package me.gergo
+
+import java.io.File
+
+fun main() {
+    val instructions = File("src/main/resources/input10.txt").readLines()
+        .map(::parseInstr)
+
+    // Part One
+    val result = listOf(20, 60, 100, 140, 180, 220).map {
+        val cpu = CPU(instructions)
+        for (c in 1 until it) cpu.step()
+        it * cpu.x
+    }.sum()
+    println(result)
+
+    // Part Two
+    val cpu = CPU(instructions)
+    CRT(40, 6, cpu).draw()
+}
+
+sealed class Instr(val duration: Int)
+object Noop : Instr(1)
+data class Addx(val value: Int) : Instr(2)
+
+private class CPU(private val instructions: List<Instr>) {
+    private var instructionPointer = 0
+    private var remainingDuration = instructions[instructionPointer].duration
+    var x = 1
+
+    fun step() {
+        remainingDuration--
+        if (remainingDuration > 0) {
+            return
+        }
+
+        when (val instr = instructions[instructionPointer]) {
+            is Noop -> {}
+            is Addx -> x += instr.value
+        }
+        if (instructionPointer >= instructions.size - 1) return
+        instructionPointer++
+        remainingDuration = instructions[instructionPointer].duration
+    }
+}
+
+private class CRT(private val width: Int, private val height: Int, private val cpu: CPU) {
+    fun draw() {
+        for (y in 1..6) {
+            for (x in 0..39) {
+                print(if (cpu.x - 1 <= x && x <= cpu.x + 1) '#' else '.')
+                cpu.step()
+            }
+            println()
+        }
+    }
+}
+
+fun parseInstr(line: String): Instr {
+    val tokens = line.split(" ")
+    return if (tokens[0] == "noop") Noop
+    else Addx(tokens[1].toInt())
+}

src/main/resources/input10.txt

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+noop
+noop
+addx 5
+addx 3
+noop
+addx 14
+addx -12
+noop
+addx 5
+addx 1
+noop
+addx 19
+addx -15
+noop
+noop
+noop
+addx 7
+addx -1
+addx 4
+noop
+noop
+addx 5
+addx 1
+addx -38
+noop
+addx 21
+addx -18
+addx 2
+addx 2
+noop
+addx 3
+addx 5
+addx -6
+addx 11
+noop
+addx 2
+addx 19
+addx -18
+noop
+addx 8
+addx -3
+addx 2
+addx 5
+addx 2
+addx 3
+addx -2
+addx -38
+noop
+addx 3
+addx 4
+addx 5
+noop
+addx -2
+addx 5
+addx -8
+addx 12
+addx 3
+addx -2
+addx 5
+addx 11
+addx -31
+addx 23
+addx 4
+noop
+noop
+addx 5
+addx 3
+addx -2
+addx -37
+addx 1
+addx 5
+addx 2
+addx 12
+addx -10
+addx 3
+addx 4
+addx -2
+noop
+addx 6
+addx 1
+noop
+noop
+noop
+addx -2
+addx 7
+addx 2
+noop
+addx 3
+addx 3
+addx 1
+noop
+addx -37
+addx 2
+addx 5
+addx 2
+addx 32
+addx -31
+addx 5
+addx 2
+addx 9
+addx 9
+addx -15
+noop
+addx 3
+addx 2
+addx 5
+addx 2
+addx 3
+addx -2
+addx 2
+addx 2
+addx -37
+addx 5
+addx -2
+addx 2
+addx 5
+addx 2
+addx 16
+addx -15
+addx 4
+noop
+addx 1
+addx 2
+noop
+addx 3
+addx 5
+addx -1
+addx 5
+noop
+noop
+noop
+noop
+addx 3
+addx 5
+addx -16
+noop