Initial data commit

Task/Stern-Brocot-sequence/Haskell/stern-brocot-sequence-1.hs

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+import Data.List (elemIndex)
+
+sb :: [Int]
+sb = 1 : 1 : f (tail sb) sb
+  where
+    f (a : aa) (b : bb) = a + b : a : f aa bb
+
+main :: IO ()
+main = do
+  print $ take 15 sb
+  print
+    [ (i, 1 + (\(Just i) -> i) (elemIndex i sb))
+      | i <- [1 .. 10] <> [100]
+    ]
+  print $
+    all (\(a, b) -> 1 == gcd a b) $
+      take 1000 $ zip sb (tail sb)

Task/Stern-Brocot-sequence/Haskell/stern-brocot-sequence-2.hs

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+import Data.Function (on)
+import Data.List (nubBy, sortOn)
+import Data.Ord (comparing)
+
+------------------ STERN-BROCOT SEQUENCE -----------------
+
+sternBrocot :: [Int]
+sternBrocot = head <$> iterate go [1, 1]
+  where
+    go (a : b : xs) = (b : xs) <> [a + b, b]
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main = do
+  print $ take 15 sternBrocot
+  print $
+    take 10 $
+      nubBy (on (==) fst) $
+        sortOn fst $
+          takeWhile ((110 >=) . fst) $
+            zip sternBrocot [1 ..]
+  print $
+    take 1 $
+      dropWhile ((100 /=) . fst) $
+        zip sternBrocot [1 ..]
+  print $
+    (all ((1 ==) . uncurry gcd) . (zip <*> tail)) $
+      take 1000 sternBrocot