[FP/HW4] Solved exercise 2

1 files changed, 43 insertions, 4 deletions

diff --git a/Year 2/Functional Programming/hw4.hs b/Year 2/Functional Programming/hw4.hs
index 8e35f4d..f548527 100644
--- a/Year 2/Functional Programming/hw4.hs
+++ b/Year 2/Functional Programming/hw4.hs
@@ -1,6 +1,7 @@
--- Задача 1
-
 import Data.List
+import Data.Char
+
+-- Задача 1
 
 subtr :: String -> String -> String
 subtr a b = filter (\c -> not (c `elem` b)) a
@@ -41,13 +42,51 @@ decode i = read $ parseNumbers (getSegments $ sortBy (\s1 s2 -> compare (length
                         else if      (seg!!2) `hasAllCharsIn` d  then '9' -- ако cf се съдържа (и bd се съдържа)
                                                                  else '6'
 
+-- Задача 2
 
+toBitString :: Char -> String
+toBitString c = calc (digitToInt c) 8
+  where
+    calc :: Int -> Int -> String
+    calc _ 0 = []
+    calc n p
+      | n - p >= 0 = '1' : (calc (n - p) (p `div` 2))
+      | otherwise  = '0' : (calc n       (p `div` 2))
+
+binaryToInt :: String -> Int
+binaryToInt b = calc b 0
+  where
+    calc [] acc = acc
+    calc b acc
+      | (head b) == '1' = calc (tail b) (acc + 2^((length b) - 1))
+      | otherwise = calc (tail b) acc
+
+versionSum :: String -> Int
+versionSum i = calc (concat (map toBitString i)) 0
+  where
+    calc [] vs = vs
+    calc p vs
+      | length p < 11 = vs
+        -- Пакет-литерал
+      | (take 3 (drop 3 p)) == "100" = calc (drop (6 + literalLength (drop 6 p) 0) p) (vs + binaryToInt (take 3 p))
+        -- Пакет-оператор
+      | otherwise = if p!!6 == '0' then calc (drop 22 p) (vs + binaryToInt (take 3 p))
+                                   else calc (drop 18 p) (vs + binaryToInt (take 3 p))
+
+    literalLength li acc
+      | head li == '0' = acc + 5
+      | otherwise = literalLength (drop 5 li) (acc + 5)
 
 -- main
 
 main :: IO()
 main = do
   sample <- readFile "sample.txt"
-  print(sum (map (\l -> decode l) (lines sample)))
+  print(sum (map (\l -> decode l) (lines sample))) -- -> 61229
   input <- readFile "input.txt"
-  print(sum (map (\l -> decode l) (lines input)))
+  print(sum (map (\l -> decode l) (lines input)))  -- -> 983026
+
+  print(versionSum "8A004A801A8002F478")             -- -> 16
+  print(versionSum "620080001611562C8802118E34")     -- -> 12
+  print(versionSum "C0015000016115A2E0802F182340")   -- -> 23
+  print(versionSum "A0016C880162017C3686B18A3D4780") -- -> 31