June 2018 Update

2018-06-22 20:57:24 +00:00 · 2018-06-22 20:57:24 +00:00 · 22f33d4004
commit 22f33d4004
parent ba8067c3b7
5278 changed files with 84726 additions and 14379 deletions
--- a/Task/Fibonacci-sequence/Haskell/fibonacci-sequence-7.hs
+++ b/Task/Fibonacci-sequence/Haskell/fibonacci-sequence-7.hs
@ -1 +1,8 @@
-fib = 0 : 1 : next fib where next (a: t@(b:_)) = (a+b) : next t
+{-# Language LambdaCase #-}
+import Data.MemoTrie
+fib :: Integer -> Integer
+fib = memo $ \case
+   0 -> 0
+   1 -> 1
+   n | n>0 -> fib (n-1) + fib (n-2)
+     | otherwise -> fib (n+2) - fib (n+1)