1 files changed, 90 insertions, 0 deletions
diff --git a/Day13.cs b/Day13.cs
new file mode 100644
index 0000000..c666c72
--- /dev/null
+++ b/Day13.cs
@@ -0,0 +1,90 @@
+using aoc2019.lib;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace aoc2019
+{
+    internal class Day13 : Day
+    {
+        public override int DayNumber => 13;
+
+        private readonly IntCodeVM vm;
+        private readonly Dictionary<(int x, int y), int> board;
+
+        public Day13()
+        {
+            vm = new IntCodeVM(Input.First());
+            board = new Dictionary<(int, int), int>();
+        }
+
+        private void UpdateTiles(IEnumerable<long> queue)
+        {
+            var input = queue.Select(i => (int)i).ToList();
+
+            for (var i = 0; i < input.Count - 2; i += 3)
+            {
+                var x = input[i];
+                var y = input[i + 1];
+                var val = input[i + 2];
+
+                if (board.ContainsKey((x, y)))
+                    board[(x, y)] = val;
+                else
+                    board.Add((x, y), val);
+            }
+
+        }
+
+        private void PrintBoard()
+        {
+            foreach (var tile in board)
+            {
+                var (x, y) = tile.Key;
+                if (x < 0 || y < 0) continue;
+                Console.SetCursorPosition(x, y);
+                Console.Write(tile.Value switch
+                {
+                    0 => " ",
+                    1 => "|",
+                    2 => "B",
+                    3 => "_",
+                    4 => ".",
+                    _ => tile.Value
+                });
+            }
+        }
+
+        public override string Part1()
+        {
+            vm.Reset();
+            vm.Run();
+            return $"{vm.output.Where((v, i) => (i + 1) % 3 == 0 && v == 2).Count()}";
+        }
+
+        public override string Part2()
+        {
+            vm.Reset();
+            vm.memory[0] = 2;
+            var printboard = false;
+            var gameTicks = 0;
+            if (printboard) Console.Clear();
+
+            var haltType = IntCodeVM.HaltType.Waiting;
+            while (haltType == IntCodeVM.HaltType.Waiting)
+            {
+                haltType = vm.Run();
+                UpdateTiles(vm.output);
+
+                var (ball, _) = board.First(t => t.Value == 4).Key;
+                var (paddle, _) = board.First(t => t.Value == 3).Key;
+                vm.AddInput(ball > paddle ? 1 : ball < paddle ? -1 : 0);
+
+                gameTicks++;
+                if (printboard) PrintBoard();
+            }
+
+            return $"after {gameTicks} moves, the score is: {board[(-1, 0)]}";
+        }
+    }
+}