Adds solution 1

.gitignore

@@ -0,0 +1,31 @@
+
+# Created by https://www.gitignore.io/api/haskell
+# Edit at https://www.gitignore.io/?templates=haskell
+
+### Haskell ###
+dist
+dist-*
+cabal-dev
+*.o
+*.hi
+*.chi
+*.chs.h
+*.dyn_o
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+.stack-work/
+cabal.project.local
+cabal.project.local~
+.HTF/
+.ghc.environment.*
+
+# End of https://www.gitignore.io/api/haskell
+
+*/input

1/1.hs

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+module Main where
+
+import qualified Data.IntSet as Set
+
+main = do
+  changes <- map (read . dropPlus) . lines <$> getContents
+  let sums = scanl (+) 0 . cycle $ changes
+  putStrLn $ show $ sum changes
+  putStrLn $ show $ firstDup sums
+
+dropPlus ('+':cs) = cs
+dropPlus cs = cs
+
+firstDup :: [Int] -> Int
+firstDup = go Set.empty
+  where
+    go seen (x:xs) = if x `Set.member` seen then x else go (Set.insert x seen) xs