From 21a27d5fc77d5a40f87e68aec0ed0aceb0e1231a Mon Sep 17 00:00:00 2001
From: kageru <kageru@encode.moe>
Date: Fri, 14 Dec 2018 23:34:16 +0100
Subject: [PATCH] (Kotlin) day 13 part 2 done

---
 13/Cart.kt   |  2 --
 13/main.kt   | 16 ++++------------
 13/main_2.kt | 10 +++++-----
 3 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/13/Cart.kt b/13/Cart.kt
index a92d814..34cc7d0 100644
--- a/13/Cart.kt
+++ b/13/Cart.kt
@@ -6,14 +6,12 @@ public class Train {
         this.x = x
         this.y = y
         this.nextTurn = Turn.LEFT
-        this.alive = true
     }
 
     var direction: Int
     var nextTurn: Turn
     var x: Int
     var y: Int
-    var alive: Boolean
 
     fun makeTurn(turn: Turn) {
         this.direction += turn.dir
diff --git a/13/main.kt b/13/main.kt
index 8463232..b864df3 100644
--- a/13/main.kt
+++ b/13/main.kt
@@ -26,8 +26,8 @@ class Main() {
     fun findCrash(trains: MutableList<Train>) {
         var positions = HashSet<Pair<Int, Int>>(trains.size - 1)
         trains.map{ t -> Pair(t.x, t.y) }.forEach{ p ->
-            if (!(p in positions)) { positions.add(p); println("adding $p") }
-            else { println(p) }
+            if (p !in positions) positions.add(p)
+            else println(p)
         }
     }
 
@@ -50,13 +50,11 @@ class Main() {
             3 -> t.x -= 1
             else -> throw IllegalArgumentException("this shouldn’t happen either selphyDerp")
         }
-        //println("x ${t.x}, y ${t.y}")
         val current = field[t.y][t.x]
-        //println(current)
         when (current) {
             Field.VERTICAL, Field.HORIZONTAL -> {}
-            Field.TOP_LEFT -> {println("hit $current, changing dir from ${t.direction} to ${t.direction xor 1}"); t.direction = t.direction xor 1}
-            Field.TOP_RIGHT -> {println("hit $current, changing dir from ${t.direction} to ${t.direction xor 3}"); t.direction = t.direction xor 3}
+            Field.TOP_LEFT -> t.direction = t.direction xor 1
+            Field.TOP_RIGHT -> t.direction = t.direction xor 3
             Field.INTERSECTION -> t.crossIntersection()
             Field.EMPTY -> throw IllegalStateException("I shouldn’t be here")
         }
@@ -76,8 +74,6 @@ class Main() {
             for ((x, char) in line.toCharArray().withIndex()) {
                 if (char in TRAINS) {
                     val newTrain = parseTrain(char, x, y)
-                    println("train at $x, $y")
-                    println(char)
                     trains.add(newTrain)
                 }
                 fields.add(parseField(char))
@@ -86,13 +82,9 @@ class Main() {
         }
         var positions = HashSet<Pair<Int, Int>>(trains.size)
         positions.addAll(trains.map{ t -> Pair(t.x, t.y) })
-        //println(field[75])
         var current = 0
         while (positions.size == trains.size) {
             trains[current] = moveTrain(trains[current])
-            //trains.forEach{ t -> moveTrain(t) }
-            //val pos = Pair(trains[15].y, trains[15].x)
-            //println("$pos: ${field[pos.first][pos.second]}: ${trains[15].direction}")
             positions.clear()
             positions.addAll(trains.map{ t -> Pair(t.x, t.y) })
             current = (current + 1) % trains.size
diff --git a/13/main_2.kt b/13/main_2.kt
index 35ba8a1..b1f6024 100644
--- a/13/main_2.kt
+++ b/13/main_2.kt
@@ -24,8 +24,8 @@ class Main() {
     }
 
     fun cleanUpAfterCrash(trains: MutableList<Train>): Pair<Int, Int> {
-        for ((i, train) in trains.filter{ it.alive }.withIndex()) {
-            for ((j, t2) in trains.filter{ it.alive }.withIndex()) {
+        for ((i, train) in trains.withIndex()) {
+            for ((j, t2) in trains.withIndex()) {
                 if (train != t2 && train.x == t2.x && train.y == t2.y) {
                     return Pair(i, j)
                 }
@@ -92,9 +92,9 @@ class Main() {
                 trains[i] = moveTrain(train)
                 positions.clear()
                 positions.addAll(trains.map{ t -> Pair(t.x, t.y) })
-                if (trains.size > positions.size) {
+                // This is not ideal, but there is never more than one crash per tick
+                if (trains.size > positions.size && !crash) {
                     remove = cleanUpAfterCrash(trains)
-                    println("removing $remove")
                     crash = true
                 }
             }
@@ -102,9 +102,9 @@ class Main() {
                 trains.removeAll(listOf(trains[remove.first], trains[remove.second]))
                 crash = false
             }
+            trains = trains.sortedBy{ it.y * 200 + it.x }.toMutableList()
         }
         println("${trains[0].x},${trains[0].y}")
-        println("done")
     }
     }
 }