From c0fa77e427c8a442ed32917d0ff2f3bfa626ff46 Mon Sep 17 00:00:00 2001
From: Corey Farwell <coreyf@rwell.org>
Date: Sat, 17 Nov 2018 12:30:51 -0500
Subject: [PATCH] 2017 - day 1 - part 1

---
 2016/day-1/run.hs | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 2016/day-1/run.hs

diff --git a/2016/day-1/run.hs b/2016/day-1/run.hs
new file mode 100644
index 0000000..d086f4f
--- /dev/null
+++ b/2016/day-1/run.hs
@@ -0,0 +1,49 @@
+import qualified Data.Text as T
+
+type Pos = (Integer, Integer)
+type Rot = Integer
+type Steps = Integer
+type Dist = Integer
+type Instr = String
+type Input = String
+
+instrToRot :: Instr -> Rot -> Rot
+instrToRot instr currRot =
+  case head instr of
+    'R' -> currRot + 1
+    'L' -> currRot - 1
+
+instrToSteps :: Instr -> Steps
+instrToSteps instr = read $ tail instr
+
+rotAndStepsToDeltaPos :: Rot -> Steps -> Pos
+rotAndStepsToDeltaPos rot steps =
+  case rot `mod` 4 of
+    0 -> (0, steps)
+    1 -> (steps, 0)
+    2 -> (0, -steps)
+    3 -> (-steps, 0)
+
+posToDist :: Pos -> Dist
+posToDist (x, y) = abs x + abs y
+
+splitInput :: Input -> [Instr]
+splitInput input = map T.unpack $ T.splitOn (T.pack ", ") (T.pack input)
+
+instrsToPos :: [Instr] -> Pos
+instrsToPos instrs = snd $ foldl prevStateToNextState (0, (0, 0)) instrs
+
+instrsToDist instrs = posToDist $ instrsToPos instrs
+
+type State = (Rot, Pos)
+
+prevStateToNextState :: State -> Instr -> State
+prevStateToNextState (prevRot, (prevX, prevY)) instr =
+  (nextRot, (prevX + deltaX, prevY + deltaY))
+    where nextRot = instrToRot instr prevRot
+          nextSteps = instrToSteps instr
+          (deltaX, deltaY) = rotAndStepsToDeltaPos nextRot nextSteps
+
+inputInstrs = "R4, R5, L5, L5, L3, R2, R1, R1, L5, R5, R2, L1, L3, L4, R3, L1, L1, R2, R3, R3, R1, L3, L5, R3, R1, L1, R1, R2, L1, L4, L5, R4, R2, L192, R5, L2, R53, R1, L5, R73, R5, L5, R186, L3, L2, R1, R3, L3, L3, R1, L4, L2, R3, L5, R4, R3, R1, L1, R5, R2, R1, R1, R1, R3, R2, L1, R5, R1, L5, R2, L2, L4, R3, L1, R4, L5, R4, R3, L5, L3, R4, R2, L5, L5, R2, R3, R5, R4, R2, R1, L1, L5, L2, L3, L4, L5, L4, L5, L1, R3, R4, R5, R3, L5, L4, L3, L1, L4, R2, R5, R5, R4, L2, L4, R3, R1, L2, R5, L5, R1, R1, L1, L5, L5, L2, L1, R5, R2, L4, L1, R4, R3, L3, R1, R5, L1, L4, R2, L3, R5, R3, R1, L3"
+
+main = putStrLn $ show $ instrsToDist $ splitInput $ inputInstrs
\ No newline at end of file
-- 
2.51.2