day 12/2016

Author: agrison

src/main/kotlin/me/grison/aoc/Strings.kt

@@ -133,7 +133,9 @@ fun String.subs(x: Int, y: Int) = substring(x, y)
 
 operator fun String.get(x: Int, y: Int) = substring(x, y)
 
-fun String.isAscii() = all { it.toInt() <= 255 }
+fun String.isAscii() = all { it.code <= 255 }
+
+fun String.isDigits() = all { it.code in 48..57 }
 
 fun String.split(at: Int) = listOf(this.take(at), this.drop(at))
 

src/main/kotlin/me/grison/aoc/y2016/Day12.kt

@@ -0,0 +1,45 @@
+package me.grison.aoc.y2016
+
+import me.grison.aoc.Day
+import me.grison.aoc.isDigits
+import me.grison.aoc.words
+
+class Day12 : Day(12, 2016) {
+ override fun title() = "Leonardo's Monorail"
+
+ private val instructions = inputList.map { "$it ." }.map { it.words() }
+
+ override fun partOne() = emulate().getValue("a")
+
+ override fun partTwo() = emulate(c = 1).getValue("a")
+
+ private fun getValue(registers: Map<String, Int>, x: String) =
+ if (x.isDigits()) {
+ x.toInt()
+ } else {
+ registers.getValue(x)
+ }
+
+ private fun emulate(a: Int = 0, b: Int = 0, c: Int = 0, d: Int = 0): Map<String, Int> {
+ var pc = 0
+ val registers = mutableMapOf("a" to a, "b" to b, "c" to c, "d" to d)
+
+ loop@ while (pc < instructions.size) {
+ val (cmd, x, y) = instructions[pc]
+
+ when (cmd) {
+ "cpy" -> registers[y] = getValue(registers, x)
+ "inc" -> registers[x] = registers.getValue(x) + 1
+ "dec" -> registers[x] = registers.getValue(x) - 1
+ "jnz" -> if (getValue(registers, x) != 0) {
+ pc += y.toInt()
+ continue@loop
+ }
+ }
+
+ pc += 1
+ }
+
+ return registers
+ }
+}

src/main/resources/2016/12.txt

@@ -0,0 +1,23 @@
+cpy 1 a
+cpy 1 b
+cpy 26 d
+jnz c 2
+jnz 1 5
+cpy 7 c
+inc d
+dec c
+jnz c -2
+cpy a c
+inc a
+dec b
+jnz b -2
+cpy c b
+dec d
+jnz d -6
+cpy 17 c
+cpy 18 d
+inc a
+dec d
+jnz d -2
+dec c
+jnz c -5

src/test/kotlin/me/grison/aoc/y2016/AllDaysTest.kt

@@ -22,7 +22,7 @@ class AllDaysTest {
 // Answer({ Day09() }, 251, 898),
 // Answer({ Day10() }, 360154, 5103798),
 // Answer({ Day11() }, "vzbxxyzz", "vzcaabcc"),
-// Answer({ Day12() }, 119433, 68466),
+ Answer({ Day12() }, 318117, 9227771),
 // Answer({ Day13() }, 664, 640),
 // Answer({ Day14() }, 2696, 1084),
 // Answer({ Day15() }, 222870, 117936),