hanoi assignment

haskell/04-hanoi/README.md

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+# Assignment - Tower of Hanoi {.alert}
+
+The Tower of Hanoi is a classic mathematical puzzle that involves three rods and a number of disks of different sizes. 
+The puzzle starts with all the disks stacked in ascending order of size on one rod (the source rod), with the smallest disk on top. 
+The objective is to move the entire stack to another rod (the destination rod), following these rules:
+
+1. Only one disk can be moved at a time.
+2. Each move consists of taking the top disk from one rod and placing it on another rod.
+3. No disk may be placed on top of a smaller disk.
+
+**Your task:**
+
+Implement a function that solves the Tower of Hanoi problem for `n` disks. The rods are represented as Chars (e.g. 'a','b','c'). The result shall be a list of moving instructions. Add your implementation to the file `04-hanoi/hanoi.hs` that already contains a test and a helper function that creates the move instruction for a single move.

haskell/04-hanoi/hanoi.hs

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+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+{-# HLINT ignore "Use void" #-}
+import Test.HUnit
+
+-- some helper function that describes a single move
+move :: Int -> Char -> Char -> String
+move n src dst = "move disk " ++ show n ++ " from " ++ [src] ++ " to " ++ [dst]
+
+-- transfers a number of disks (the Int) from a source (the first Char) rod to a destination (the second Char) rod via a temp (the third char) rod
+-- returns a list of required operations
+hanoi :: (Int,Char,Char,Char) -> [String]
+
+--TODO: implement here
+
+-- Source, Destination, Temp
+hanoiTests :: [((Int, Char, Char, Char), [String])]
+hanoiTests =
+  [ ( (1, 'a', 'c', 'b'),
+      [ "move disk 1 from a to c"
+      ]
+    ),
+    ( (1, 'b', 'a', 'c'),
+      [ "move disk 1 from b to a"
+      ]
+    ),
+    ( (2, 'a', 'c', 'b'),
+      [ "move disk 1 from a to b",
+        "move disk 2 from a to c",
+        "move disk 1 from b to c"
+      ]
+    ),
+    ( (3, 'a', 'c', 'b'),
+      [ "move disk 1 from a to c",
+        "move disk 2 from a to b",
+        "move disk 1 from c to b",
+        "move disk 3 from a to c",
+        "move disk 1 from b to a",
+        "move disk 2 from b to c",
+        "move disk 1 from a to c"
+      ]
+    ),
+    ( (4, 'a', 'c', 'b'),
+      [ "move disk 1 from a to b",
+        "move disk 2 from a to c",
+        "move disk 1 from b to c",
+        "move disk 3 from a to b",
+        "move disk 1 from c to a",
+        "move disk 2 from c to b",
+        "move disk 1 from a to b",
+        "move disk 4 from a to c",
+        "move disk 1 from b to c",
+        "move disk 2 from b to a",
+        "move disk 1 from c to a",
+        "move disk 3 from b to c",
+        "move disk 1 from a to b",
+        "move disk 2 from a to c",
+        "move disk 1 from b to c"
+      ]
+    )
+  ]
+
+hanoiTestCases :: [Test]
+hanoiTestCases = map (\(input, expected) -> TestCase (assertEqual ("hanoi " ++ show input) expected (hanoi input))) hanoiTests
+
+tests :: Test
+tests = TestList hanoiTestCases
+
+main :: IO ()
+main = runTestTT tests >> return ()