2018 day 1

aoc/src/main/scala/aoc/Main.scala

@@ -7,6 +7,7 @@ object Main {
   val years = Map(
     "2016" -> y2016.!,
     "2017" -> y2017.!,
+    "2018" -> y2018.!,
   )
 
   def main(args: Array[String]): Unit = {

aoc/src/main/scala/aoc/package.scala

@@ -22,4 +22,12 @@ package object aoc {
 
   }
 
+  def uniquePrefix[A](as: Stream[A]): Stream[A] = {
+    def go(as: Stream[A], seen: Set[A]): Stream[A] = as match {
+      case h #:: t if !seen(h) => h #:: go(t, seen + h)
+      case _ => Stream.empty[A]
+    }
+    go(as, Set.empty)
+  }
+
 }

aoc/src/main/scala/aoc/y2017/Day06.scala

@@ -4,14 +4,6 @@ import aoc._
 
 object Day06 extends Day {
 
-  def uniquePrefix[A](as: Stream[A]): Stream[A] = {
-    def go(as: Stream[A], seen: Set[A]): Stream[A] = as match {
-      case h #:: t if !seen(h) => h #:: go(t, seen + h)
-      case _ => Stream.empty[A]
-    }
-    go(as, Set.empty)
-  }
-
   case class State(blocks: List[Int]) {
 
     def step: State = {

aoc/src/main/scala/aoc/y2018/Day01.scala

@@ -0,0 +1,24 @@
+package aoc.y2018
+
+import aoc._
+
+object Day01 extends Day {
+
+  override def part1(input: String): String = {
+    input.lines.map(_.toInt).sum.toString
+  }
+
+  override def part2(input: String): String = {
+    println(input.lines.size)
+    val i: List[Int] = input.lines.map(_.toInt).toList
+    val inet = i.zipWithIndex.map {
+      case (f, index) => f + i.take(index).sum
+    }
+    val net = i.sum
+    val fcs = 0 #:: Stream.iterate(inet)(cl => cl.map(_ + net)).flatten
+    val us = uniquePrefix(fcs)
+    val nf = fcs(us.size)
+    nf.toString
+  }
+
+}

aoc/src/main/scala/aoc/y2018/package.scala

@@ -0,0 +1,9 @@
+package aoc
+
+package object y2018 extends Year {
+
+  override def days: Map[String, Day] = Map(
+    "1" -> Day01
+  )
+
+}