Day 7 Part 2

07/Main.idr

@@ -1,4 +1,5 @@
 import Data.List
+import Data.List1
 import Data.Vect
 import Data.String
 import System.File.ReadWrite
@@ -191,8 +192,6 @@ applyCommands xs x = helper (Stk []) xs x
           do result <- foldlM (insertEntry (current stack)) node entries
              helper stack ys result
 
-
-
 part1 : String ->  IO ()
 part1 input =
   case parseCmds (lines input) of
@@ -204,9 +203,37 @@ part1 input =
           let wanted = sum . filter (<= 100000) . map size . directories $  node
           in putStrLn $ "Part 1: " ++ show wanted
 
+minBy : Ord b => (a -> b) -> a -> a -> a
+minBy f x y =
+  let i = f x
+      j = f y
+  in if i < j then x else y
+
+part2 : String -> IO ()
+part2 input =
+  case parseCmds (lines input) of
+    Nothing => putStrLn "Failed to parse commands"
+    (Just commands) =>
+      case applyCommands commands emptyNode of
+        Nothing => putStrLn "Failed to apply commands"
+        (Just node) =>
+          let totalSpace = 70000000
+              neededSpace = 30000000
+              freeSpace = minus totalSpace (size node)
+              deficit = minus neededSpace freeSpace
+              canidates = filter ((>= deficit) . size) (directories node)
+          in case Data.List1.fromList canidates of
+               Nothing => putStrLn "Only one canidate?"
+               (Just canidates) =>
+                 let smallest = foldl1 (minBy size) canidates
+                 in putStrLn $ "Part 2: " ++ (show (size smallest))
+
+
 partial main : IO ()
 main =
   do file <- readFile "input"
      case file of
-       (Right contents) => part1 contents
+       (Right contents) =>
+         do part1 contents
+            part2 contents
        (Left err) => printLn err