Solved trampoline problem for day 5

This included learning more about Sequence and Array data structures
for performance as List "mutation" was very slow. Seq data structure
was enough to run nearly 50% faster than the equivalent python code.

> $ time python day05.py
> 21841249
>
> real	0m14.671s
> user	0m14.646s
> sys	0m0.015s
>
> $ time result/bin/trampoline
> 21841249
>
> real	0m7.478s
> user	0m7.422s
> sys	0m0.048s

aoc2017.cabal

@@ -0,0 +1,11 @@
+name: aoc2017
+version: 1.0.0
+license: BSD3
+license-file: LICENSE
+cabal-version: >= 1.18
+build-type: Simple
+
+executable trampoline
+    build-depends: base < 5, mtl, containers, array
+    main-is: day05-trampoline.hs
+    default-language: Haskell2010

day05-trampoline.hs

@@ -1,10 +1,40 @@
+module Main where
 
+import qualified Data.Sequence as S
 
-data JumpState = JumpState { moves :: [Int], cursor :: Int }
+type Cursor = Int
+type Count = Int
 
 
+-- startState = (0, 0, [0,3,0,1,-3])
+
+inside :: Int -> S.Seq Int -> Bool
+inside idx xs = idx >= 0 && idx < S.length xs
+
+
+mutate :: Int -> S.Seq Int -> S.Seq Int
+mutate cursor xs = S.adjust inc cursor xs
+
+mutate' :: Int -> S.Seq Int -> S.Seq Int
+mutate' cursor xs = S.adjust (if (S.index xs cursor) > 2 then dec else inc) cursor xs
+
+dec :: Int -> Int
+dec n = n - 1
+
+inc :: Int -> Int
+inc n = n + 1
+
+
+jump :: Count -> Cursor -> S.Seq Int -> Count
+jump count cursor xs
+  | inside cursor xs = count `seq` cursor `seq` jump (inc count)
+                                                     (cursor + (S.index xs cursor))
+                                                     (mutate' cursor xs)
+  | otherwise        = count
+
 main :: IO ()
 main = do
-  input <- readFile "day05.txt"
-  let jumps = map read $ lines input :: [Int]
-  print $ show $ length jumps
+  strings <- words <$> readFile  "../AoC2017/day05.txt"
+  --let strings = words "0 3 0 1 -3"
+  print $ jump 0 0 (S.fromList (map read strings :: [Int]))
+

day05.py

@@ -0,0 +1,28 @@
+
+def inside(idx, xs):
+    return not (idx < 0 or idx >= len(xs))
+
+
+testList = [0,3,0,1,-3]
+count = 0
+cursor = 0
+
+f = open("day05.txt")
+testList = []
+
+for line in f:
+    testList.append(int(line))
+
+while (inside(cursor, testList)):
+    count += 1
+    offset = testList[cursor]
+    if (offset > 2):
+        testList[cursor] -= 1
+    else:
+        testList[cursor] += 1
+    cursor += offset
+print (count)
+
+
+
+