Day 3

diff --git a/src/advent03/advent03.hs b/src/advent03/advent03.hs
new file mode 100644 (file)
index 0000000..e7348e4
--- /dev/null
+++ b/src/advent03/advent03.hs
@@ -0,0 +1,79 @@
+import Data.List (tails)
+import qualified Data.HashMap.Strict as M
+import Data.HashMap.Strict ((!))
+import Control.Monad.State.Lazy
+
+type Location = (Int, Int)
+type Memory = M.HashMap Location Int
+
+target :: Int
+target = 347991
+
+main :: IO ()
+main = do 
+        print $ part1 
+        print $ part2
+
+
+diagonal :: Int -> [Int]
+diagonal n = scanl (+) 1 $ scanl (+) n $ repeat 8
+dr = diagonal 8
+ul = diagonal 4
+ur = diagonal 2
+dl = diagonal 6
+
+
+interleave :: [[a]] -> [a]
+interleave ([]:_) = []
+interleave xss = map head xss ++ interleave (map tail xss)
+
+
+countedDiags = interleave [(zip [0..] ur), (zip [0..] ul), (zip [0..] dl), (zip [0..] dr)]
+
+part1 = let corners =  head $ dropWhile ((< target) . snd . head . tail) $ tails countedDiags
+            (pcd, pcv) = head corners
+            (ncd, ncv) = head $ tail corners
+            result = if pcd == ncd 
+                        then if (target - pcv + 2) < ncv - target
+                             then pcd * 2 - (target - pcv)
+                             else ncd * 2 - (ncv - target)
+                     else if (target - pcv + 1) < ncv - target
+                             then pcd * 2 - (target - pcv) + 2
+                             else ncd * 2 - (ncv - target)          
+    in result
+
+
+part2 = (!) memoryValues $ head $ dropWhile (\l -> memoryValues!l <= target) locations
+    where memoryValues = execState (updateMemory (take 100 $ drop 1 locations)) emptyMemory   
+
+up    (a, b) = (a, b + 1)
+down  (a, b) = (a, b - 1)
+left  (a, b) = (a - 1, b)
+right (a, b) = (a + 1, b)
+directions = [right, up, left, down]
+
+locations = scanl (\c f -> f c) (0,0) $ concat $ zipWith replicate steps (cycle directions)
+    where
+        steps = concat $ zipWith (\a b -> [a,b]) [1..] [1..]
+
+adjacentMap (r, c) = M.filterWithKey adjacent 
+    where adjacent k _ = abs (fst k - r) <= 1 && abs (snd k - c) <= 1     
+
+adjacentMapSum here = M.foldr (+) 0 . adjacentMap here
+
+
+emptyMemory = M.singleton (0, 0) 1  
+
+updateMemoryOnce :: Location -> State Memory Int
+updateMemoryOnce here = 
+    do m0 <- get
+       let total = adjacentMapSum here m0
+       put (M.insert here total m0)
+       return total
+
+updateMemory :: [Location] -> State Memory Int
+updateMemory [] = do return 0
+updateMemory (l:ls) = 
+    do  updateMemoryOnce l
+        updateMemory ls
+

diff --git a/src/advent03/advent03.ipynb b/src/advent03/advent03.ipynb
new file mode 100644 (file)
index 0000000..f06014d
--- /dev/null
+++ b/src/advent03/advent03.ipynb
@@ -0,0 +1,1509 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "{-# LANGUAGE FlexibleContexts #-}\n",
+    "{-# LANGUAGE MultiWayIf #-}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import Data.List (tails)\n",
+    "import qualified Data.HashMap.Strict as M\n",
+    "import Data.HashMap.Strict ((!))\n",
+    "import Control.Monad.State.Lazy"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "offsets2 = repeat 8"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[8,8,8]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 3 offsets2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[8,16,24]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 3 $ scanl (+) 8 offsets2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "diagonal n = scanl (+) 1 $ scanl (+) n $ repeat 8"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,9,25,49,81]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "dr = diagonal 8\n",
+    "take 5 dr"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,5,17,37,65]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "ul = diagonal 4\n",
+    "take 5 ul"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,3,13,31,57]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "ur = diagonal 2\n",
+    "take 5 ur"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,7,21,43,73]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "dl = diagonal 6\n",
+    "take 5 dl"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "73"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "dl!!4"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(4,73)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "head $ dropWhile ((< 70) . snd) $ zip [0..] dl"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(4,81)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "head $ dropWhile ((< 70) . snd) $ zip [0..] dr"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[0,1,2]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 3 [0..]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "interleave4 (p:ps) (q:qs) (r:rs) (s:ss) = p:q:r:s:interleave4 ps qs rs ss"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "interleave ([]:_) = []\n",
+    "interleave xss = map head xss ++ interleave (map tail xss)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[(0,1),(1,3),(1,5),(1,7),(1,9),(2,13),(2,17),(2,21),(2,25),(3,31),(3,37),(3,43),(3,49),(4,57),(4,65),(4,73),(4,81),(5,91),(5,101),(5,111)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 $ drop 3 $ interleave4 (zip [0..] ur) (zip [0..] ul) (zip [0..] dl) (zip [0..] dr)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,1,1,1]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "map head [ur, ul, dl, dr]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[[3,13],[5,17],[7,21],[9,25]]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "map (take 2 . tail) [ur, ul, dl, dr]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">(map head [ur, ul, dl, dr]) : [[10, 11, 12, 13, 14, 15, 16, 17]]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">map head [ur, ul, dl, dr] : [[10, 11, 12, 13, 14, 15, 16, 17]]</div></div>"
+      ],
+      "text/plain": [
+       "Line 1: Redundant bracket\n",
+       "Found:\n",
+       "(map head [ur, ul, dl, dr]) : [[10, 11, 12, 13, 14, 15, 16, 17]]\n",
+       "Why not:\n",
+       "map head [ur, ul, dl, dr] : [[10, 11, 12, 13, 14, 15, 16, 17]]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[1,1,1,1,10,11,12,13,14,15,16,17]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "concat $  (map head [ur, ul, dl, dr]) : [[10, 11, 12, 13, 14, 15, 16, 17]]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[0,10,20,30,1,11,21,31,2,12,22,32]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "interleave [[0,1,2], [10,11,12], [20, 21, 22], [30, 31, 32]]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,1,1,1,3,5,7,9,13,17,21,25,31,37,43,49,57,65,73,81]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 $ interleave [ur, ul, dl, dr]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 23,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[zip [0 ..] ur, (zip [0 ..] ul), (zip [0 ..] dl), (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), zip [0 ..] ul, (zip [0 ..] dl), (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), zip [0 ..] dl, (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl), zip [0 ..] dr]</div></div>"
+      ],
+      "text/plain": [
+       "Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[zip [0 ..] ur, (zip [0 ..] ul), (zip [0 ..] dl), (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), zip [0 ..] ul, (zip [0 ..] dl), (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), zip [0 ..] dl, (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl), zip [0 ..] dr]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[(0,1),(1,3),(1,5),(1,7),(1,9),(2,13),(2,17),(2,21),(2,25),(3,31),(3,37),(3,43),(3,49),(4,57),(4,65),(4,73),(4,81),(5,91),(5,101),(5,111)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 $ drop 3 $ interleave [(zip [0..] ur), (zip [0..] ul), (zip [0..] dl), (zip [0..] dr)]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "target = 30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[zip [0 ..] ur, (zip [0 ..] ul), (zip [0 ..] dl), (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), zip [0 ..] ul, (zip [0 ..] dl), (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), zip [0 ..] dl, (zip [0 ..] dr)]</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl), zip [0 ..] dr]</div></div>"
+      ],
+      "text/plain": [
+       "Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[zip [0 ..] ur, (zip [0 ..] ul), (zip [0 ..] dl), (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), zip [0 ..] ul, (zip [0 ..] dl), (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), zip [0 ..] dl, (zip [0 ..] dr)]Line 1: Redundant bracket\n",
+       "Found:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl),\n",
+       " (zip [0 ..] dr)]\n",
+       "Why not:\n",
+       "[(zip [0 ..] ur), (zip [0 ..] ul), (zip [0 ..] dl), zip [0 ..] dr]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "countedDiags = interleave [(zip [0..] ur), (zip [0..] ul), (zip [0..] dl), (zip [0..] dr)]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><div class=\"suggestion-name\" style=\"clear:both;\">Use guards</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">result\n",
+       "  = if pcd == ncd then\n",
+       "      if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "        else ncd * 2 - (ncv - target)\n",
+       "      else\n",
+       "      if (target - pcv + 1) < ncv - target then\n",
+       "        pcd * 2 - (target - pcv) + 2 else ncd * 2 - (ncv - target)</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">result\n",
+       "  | pcd == ncd =\n",
+       "    if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "      else ncd * 2 - (ncv - target)\n",
+       "  | (target - pcv + 1) < ncv - target = pcd * 2 - (target - pcv) + 2\n",
+       "  | otherwise = ncd * 2 - (ncv - target)</div></div><div class=\"suggestion-name\" style=\"clear:both;\">Redundant bracket</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">(result, pcd, ncd, (target - pcv + 2), ncv - target)</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">(result, pcd, ncd, target - pcv + 2, ncv - target)</div></div>"
+      ],
+      "text/plain": [
+       "Line 4: Use guards\n",
+       "Found:\n",
+       "result\n",
+       "  = if pcd == ncd then\n",
+       "      if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "        else ncd * 2 - (ncv - target)\n",
+       "      else\n",
+       "      if (target - pcv + 1) < ncv - target then\n",
+       "        pcd * 2 - (target - pcv) + 2 else ncd * 2 - (ncv - target)\n",
+       "Why not:\n",
+       "result\n",
+       "  | pcd == ncd =\n",
+       "    if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "      else ncd * 2 - (ncv - target)\n",
+       "  | (target - pcv + 1) < ncv - target = pcd * 2 - (target - pcv) + 2\n",
+       "  | otherwise = ncd * 2 - (ncv - target)Line 12: Redundant bracket\n",
+       "Found:\n",
+       "(result, pcd, ncd, (target - pcv + 2), ncv - target)\n",
+       "Why not:\n",
+       "(result, pcd, ncd, target - pcv + 2, ncv - target)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(7,4,4,3,7)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "target = 58\n",
+    "let corners =  head $ dropWhile ((< target) . snd . head . tail) $ tails countedDiags\n",
+    "    (pcd, pcv) = head corners\n",
+    "    (ncd, ncv) = head $ tail corners\n",
+    "    result = if pcd == ncd \n",
+    "                then if (target - pcv + 2) < ncv - target\n",
+    "                     then pcd * 2 - (target - pcv)\n",
+    "                     else ncd * 2 - (ncv - target)\n",
+    "             else if (target - pcv + 1) < ncv - target\n",
+    "                     then pcd * 2 - (target - pcv) + 2\n",
+    "                     else ncd * 2 - (ncv - target)\n",
+    "            \n",
+    "    in (result, pcd, ncd, (target - pcv + 2), ncv - target)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><div class=\"suggestion-name\" style=\"clear:both;\">Use guards</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">result\n",
+       "  = if pcd == ncd then\n",
+       "      if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "        else ncd * 2 - (ncv - target)\n",
+       "      else\n",
+       "      if (target - pcv + 1) < ncv - target then\n",
+       "        pcd * 2 - (target - pcv) + 2 else ncd * 2 - (ncv - target)</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">result\n",
+       "  | pcd == ncd =\n",
+       "    if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "      else ncd * 2 - (ncv - target)\n",
+       "  | (target - pcv + 1) < ncv - target = pcd * 2 - (target - pcv) + 2\n",
+       "  | otherwise = ncd * 2 - (ncv - target)</div></div>"
+      ],
+      "text/plain": [
+       "Line 4: Use guards\n",
+       "Found:\n",
+       "result\n",
+       "  = if pcd == ncd then\n",
+       "      if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "        else ncd * 2 - (ncv - target)\n",
+       "      else\n",
+       "      if (target - pcv + 1) < ncv - target then\n",
+       "        pcd * 2 - (target - pcv) + 2 else ncd * 2 - (ncv - target)\n",
+       "Why not:\n",
+       "result\n",
+       "  | pcd == ncd =\n",
+       "    if (target - pcv + 2) < ncv - target then pcd * 2 - (target - pcv)\n",
+       "      else ncd * 2 - (ncv - target)\n",
+       "  | (target - pcv + 1) < ncv - target = pcd * 2 - (target - pcv) + 2\n",
+       "  | otherwise = ncd * 2 - (ncv - target)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "480"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "target = 347991\n",
+    "let corners =  head $ dropWhile ((< target) . snd . head . tail) $ tails countedDiags\n",
+    "    (pcd, pcv) = head corners\n",
+    "    (ncd, ncv) = head $ tail corners\n",
+    "    result = if pcd == ncd \n",
+    "                then if (target - pcv + 2) < ncv - target\n",
+    "                     then pcd * 2 - (target - pcv)\n",
+    "                     else ncd * 2 - (ncv - target)\n",
+    "             else if (target - pcv + 1) < ncv - target\n",
+    "                     then pcd * 2 - (target - pcv) + 2\n",
+    "                     else ncd * 2 - (ncv - target)\n",
+    "            \n",
+    "    in result"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "plainDiags = map snd countedDiags"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,3,5,7,9,13,17,21,25,31,37,43,49,57,65,73,81,91,101,111]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 $ drop 3 plainDiags"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "steps =  concat $ zipWith (\\a b -> [a,b]) [1..] [1..]\n",
+    "take 20 steps"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "up    (a, b) = (a, b + 1)\n",
+    "down  (a, b) = (a, b - 1)\n",
+    "left  (a, b) = (a - 1, b)\n",
+    "right (a, b) = (a + 1, b)\n",
+    "directions = [right, up, left, down]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 32,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<style>/* Styles used for the Hoogle display in the pager */\n",
+       ".hoogle-doc {\n",
+       "display: block;\n",
+       "padding-bottom: 1.3em;\n",
+       "padding-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-code {\n",
+       "display: block;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "}\n",
+       ".hoogle-text {\n",
+       "display: block;\n",
+       "}\n",
+       ".hoogle-name {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-head {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-sub {\n",
+       "display: block;\n",
+       "margin-left: 0.4em;\n",
+       "}\n",
+       ".hoogle-package {\n",
+       "font-weight: bold;\n",
+       "font-style: italic;\n",
+       "}\n",
+       ".hoogle-module {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".hoogle-class {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".get-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "white-space: pre-wrap;\n",
+       "}\n",
+       ".show-type {\n",
+       "color: green;\n",
+       "font-weight: bold;\n",
+       "font-family: monospace;\n",
+       "margin-left: 1em;\n",
+       "}\n",
+       ".mono {\n",
+       "font-family: monospace;\n",
+       "display: block;\n",
+       "}\n",
+       ".err-msg {\n",
+       "color: red;\n",
+       "font-style: italic;\n",
+       "font-family: monospace;\n",
+       "white-space: pre;\n",
+       "display: block;\n",
+       "}\n",
+       "#unshowable {\n",
+       "color: red;\n",
+       "font-weight: bold;\n",
+       "}\n",
+       ".err-msg.in.collapse {\n",
+       "padding-top: 0.7em;\n",
+       "}\n",
+       ".highlight-code {\n",
+       "white-space: pre;\n",
+       "font-family: monospace;\n",
+       "}\n",
+       ".suggestion-warning { \n",
+       "font-weight: bold;\n",
+       "color: rgb(200, 130, 0);\n",
+       "}\n",
+       ".suggestion-error { \n",
+       "font-weight: bold;\n",
+       "color: red;\n",
+       "}\n",
+       ".suggestion-name {\n",
+       "font-weight: bold;\n",
+       "}\n",
+       "</style><span class='err-msg'>&lt;interactive&gt;:1:1: error:<br/>    • No instance for (Show ((t10, t0) -&gt; (t10, t0))) arising from a use of ‘print’<br/>        (maybe you haven't applied a function to enough arguments?)<br/>    • In a stmt of an interactive GHCi command: print it</span>"
+      ],
+      "text/plain": [
+       "<interactive>:1:1: error:\n",
+       "    • No instance for (Show ((t10, t0) -> (t10, t0))) arising from a use of ‘print’\n",
+       "        (maybe you haven't applied a function to enough arguments?)\n",
+       "    • In a stmt of an interactive GHCi command: print it"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 $ concat $ zipWith replicate steps (cycle directions)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 33,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 steps"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "locations = scanl (\\c f -> f c) (0,0) $ concat $ zipWith replicate steps (cycle directions)\n",
+    "    where\n",
+    "        steps = concat $ zipWith (\\a b -> [a,b]) [1..] [1..]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[(0,0),(1,0),(1,1),(0,1),(-1,1),(-1,0),(-1,-1),(0,-1),(1,-1),(2,-1),(2,0),(2,1),(2,2),(1,2),(0,2),(-1,2),(-2,2),(-2,1),(-2,0),(-2,-1)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "take 20 locations"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "fromList [((0,0),1)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "M.singleton (0, 0) 1"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 37,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "fromList [((0,0),1),((0,1),4),((1,1),2),((1,0),1),((-1,1),5),((-1,0),10)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "m0 = M.fromList [((0,0), 1),((1,0), 1), ((1,1), 2), ((0,1), 4), ((-1,1), 5), ((-1,0), 10)]\n",
+    "m0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "adjacentMap (r, c) = M.filterWithKey adjacent \n",
+    "    where adjacent k _ = abs (fst k - r) <= 1 && abs (snd k - c) <= 1"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "fromList [((0,0),1),((0,1),4),((-1,1),5),((-1,0),10)]"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "adjacentMap (-1, 1) m0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "adjacentMapSum here = M.foldr (+) 0 . adjacentMap here"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "20"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "adjacentMapSum (-1, 1) m0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "type Location = (Int, Int)\n",
+    "type Memory = M.HashMap Location Int"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "emptyMemory = M.singleton (0, 0) 1    "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 44,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "updateMemoryOnce :: Location -> State Memory Int\n",
+    "updateMemoryOnce here = \n",
+    "    do m0 <- get\n",
+    "       let total = adjacentMapSum here m0\n",
+    "       put (M.insert here total m0)\n",
+    "       return total"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 45,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "updateMemory :: [Location] -> State Memory Int\n",
+    "updateMemory [] = do return 0\n",
+    "updateMemory (l:ls) = \n",
+    "    do  updateMemoryOnce l\n",
+    "        updateMemory ls"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 46,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(0,fromList [((0,0),1),((5,-1),6573553),((1,3),5336),((-1,-3),37402),((-4,4),369601),((4,-4),2909666),((0,1),4),((5,-2),6262851),((1,2),122),((-1,-4),2292124),((4,-3),48065),((-4,5),24242690),((0,2),133),((2,4),279138),((5,-3),6013560),((-3,5),23510079),((1,1),2),((-1,-1),11),((4,-2),98098),((0,3),5733),((2,5),18565223),((5,-4),2957731),((-3,4),363010),((1,0),1),((-1,-2),747),((4,-1),103128),((0,4),312453),((2,2),59),((-2,-2),362),((-5,5),24612291),((-3,3),6591),((3,-3),47108),((-4,0),875851),((0,5),20390510),((-2,-1),351),((2,3),5022),((-3,2),13486),((3,-4),2814493),((-4,1),830037),((2,0),54),((-2,-4),2179400),((3,-1),1968),((-3,1),14267),((1,5),19452043),((-4,2),787032),((2,1),57),((-2,-3),35487),((3,-2),957),((-3,0),15252),((1,4),295229),((-4,3),752688),((4,4),130654),((-4,-4),1026827),((-1,5),21383723),((3,1),2275),((-3,-1),16295),((-2,2),147),((2,-2),931),((-4,-3),1009457),((4,5),17048404),((-1,4),330785),((3,0),2105),((-3,-2),17008),((2,-1),26),((-2,3),6444),((-4,-2),975079),((3,3),2450),((-3,-3),17370),((5,5),8391037),((-2,0),330),((2,-4),2674100),((-4,-1),924406),((3,2),2391),((-3,-4),2089141),((5,4),8260383),((-2,1),304),((2,-3),45220),((4,0),109476),((-1,1),5),((1,-1),25),((3,5),17724526),((5,3),8001525),((0,-4),2411813),((4,1),116247),((-1,0),10),((1,-2),880),((3,4),266330),((5,2),7619304),((0,-3),39835),((4,2),123363),((-1,3),6155),((1,-3),42452),((5,1),7251490),((-2,4),349975),((0,-2),806),((4,3),128204),((-1,2),142),((1,-4),2539320),((5,0),6902404),((-2,5),22427493),((0,-1),23)])"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "runState (updateMemory (take 100 $ drop 1 locations)) emptyMemory"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 51,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "memoryValues = execState (updateMemory (take 100 $ drop 1 locations)) emptyMemory"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 48,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "347991"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "target"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 52,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(-2,4)"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "head $ dropWhile (\\l -> memoryValues!l <= target) locations"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "349975"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "(!) memoryValues $ head $ dropWhile (\\l -> memoryValues!l <= target) locations"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Haskell",
+   "language": "haskell",
+   "name": "haskell"
+  },
+  "language_info": {
+   "codemirror_mode": "ihaskell",
+   "file_extension": ".hs",
+   "name": "haskell",
+   "version": "8.0.2"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}