cleanup

hs-euler/ChangeLog.md

@@ -1,3 +1,3 @@
-# Changelog for euler072
+# Changelog for euler
 
 ## Unreleased changes

hs-euler/README.md

@@ -1 +1 @@
-# euler072
+# euler

hs-euler/app/Main.hs

@@ -5,57 +5,34 @@
    --package arithmoi
 -}
 
-{-
-Consider the fraction, n/d, where n and d are positive integers. If n<d and
-HCF(n,d)=1, it is called a reduced proper fraction.
-
-If we list the set of reduced proper fractions for d ≤ 8 in ascending order of
-size, we get:
-
-1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, 1/2, 4/7, 3/5, 5/8, 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 7/8
-
-It can be seen that there are 21 elements in this set.
-
-How many elements would be contained in the set of reduced proper fractions for
-d ≤ 1,000,000?
--}
 {-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE OverloadedStrings #-}
 module Main where
 
 import Protolude
 
-import Math.NumberTheory.Primes
+import System.Environment
 
-reducedProper :: Integer -> [Integer]
-reducedProper d = do
-  let pf = map fst $ factorise d
-  x <- [1..d]
-  guard (not (any (\p -> x `rem` p == 0) pf))
-  return x
+import qualified Euler072
 
--- Naive solution, took ages
-nbFractions :: Integer -> Int
-nbFractions d = foldl' (+) 0 (map (traceShowId . length . reducedProper . traceShowId) [2..d])
+solution :: Int -> Maybe (IO ())
+solution 72 = Just $ do putStr ("072: " :: Text); print Euler072.solution
+solution _ = Nothing
 
--- Write a list of all factors
-factors = concatMap (\(x,n) -> replicate n x) . factorise
+solutions = [72]
 
--- phi, Euler's totient function
--- https://en.wikipedia.org/wiki/Euler%27s_totient_function
-phi n
-  | isPrime n = n-1
-  | otherwise = prodPhi (factors n)
-  where
-    prodPhi [a] = a-1
-    prodPhi (a:b:t)
-      | a == b = a * prodPhi (b:t)
-      | otherwise = (a - 1) * prodPhi (b:t)
-
--- less than 5s
-solution n = sum $ map phi [2..n]
+readNumber :: [[Char]] -> Maybe Int
+readNumber [] = Nothing
+readNumber (s:args) = reads s & head & fmap fst
 
 main :: IO ()
 main = do
-  let n = 1000000
-  -- print $ nbFractions n -- 303963552391
-  print $ solution n
+  nbParsed <- fmap readNumber getArgs
+  case nbParsed of
+    Just nb -> fromMaybe
+                  (putErrText "I don't know the solution of this problem yet.")
+                  (solution nb)
+    Nothing -> solutions
+               & map solution
+               & map (fromMaybe (pure ()))
+               & sequence_

hs-euler/euler.cabal

@@ -2,13 +2,13 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 859091034e520db697fc23b2aeb6b27cc63dfe46541d371c8bd861b7ff922014
+-- hash: fa22c4d5b58b46bb0a1b31feef800edb37c1724fa165ed9b529637ec8b56ddc5
 
-name:           euler072
+name:           euler
 version:        0.1.0.0
-description:    Please see the README on GitHub at <https://github.com/githubuser/euler072#readme>
-homepage:       https://github.com/githubuser/euler072#readme
-bug-reports:    https://github.com/githubuser/euler072/issues
+description:    Please see the README on GitHub at <https://github.com/githubuser/euler#readme>
+homepage:       https://github.com/githubuser/euler#readme
+bug-reports:    https://github.com/githubuser/euler/issues
 author:         Author name here
 maintainer:     example@example.com
 copyright:      2019 Author name here
@@ -22,13 +22,14 @@ extra-source-files:
 
 source-repository head
   type: git
-  location: https://github.com/githubuser/euler072
+  location: https://github.com/githubuser/euler
 
 library
   exposed-modules:
+      Euler072
       Lib
   other-modules:
-      Paths_euler072
+      Paths_euler
   hs-source-dirs:
       src
   build-depends:
@@ -37,31 +38,31 @@ library
     , protolude
   default-language: Haskell2010
 
-executable euler072-exe
+executable euler
   main-is: Main.hs
   other-modules:
-      Paths_euler072
+      Paths_euler
   hs-source-dirs:
       app
   ghc-options: -O -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       arithmoi
     , base >=4.7 && <5
-    , euler072
+    , euler
     , protolude
   default-language: Haskell2010
 
-test-suite euler072-test
+test-suite euler-test
   type: exitcode-stdio-1.0
   main-is: Spec.hs
   other-modules:
-      Paths_euler072
+      Paths_euler
   hs-source-dirs:
       test
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       arithmoi
     , base >=4.7 && <5
-    , euler072
+    , euler
     , protolude
   default-language: Haskell2010

hs-euler/package.yaml

@@ -1,6 +1,6 @@
-name:                euler072
+name:                euler
 version:             0.1.0.0
-github:              "githubuser/euler072"
+github:              "githubuser/euler"
 license:             BSD3
 author:              "Author name here"
 maintainer:          "example@example.com"
@@ -17,7 +17,7 @@ extra-source-files:
 # To avoid duplicated efforts in documentation and dealing with the
 # complications of embedding Haddock markup inside cabal files, it is
 # common to point users to the README.md file.
-description:         Please see the README on GitHub at <https://github.com/githubuser/euler072#readme>
+description:         Please see the README on GitHub at <https://github.com/githubuser/euler#readme>
 
 dependencies:
 - base >= 4.7 && < 5
@@ -28,7 +28,7 @@ library:
   source-dirs: src
 
 executables:
-  euler072-exe:
+  euler:
     main:                Main.hs
     source-dirs:         app
     ghc-options:
@@ -37,10 +37,10 @@ executables:
     - -rtsopts
     - -with-rtsopts=-N
     dependencies:
-    - euler072
+    - euler
 
 tests:
-  euler072-test:
+  euler-test:
     main:                Spec.hs
     source-dirs:         test
     ghc-options:
@@ -48,4 +48,4 @@ tests:
     - -rtsopts
     - -with-rtsopts=-N
     dependencies:
-    - euler072
+    - euler

hs-euler/src/Euler072.hs

@@ -20,7 +20,7 @@ How many elements would be contained in the set of reduced proper fractions for
 d ≤ 1,000,000?
 -}
 {-# LANGUAGE NoImplicitPrelude #-}
-module Main where
+module Euler072 where
 
 import Protolude
 
@@ -37,6 +37,8 @@ reducedProper d = do
 nbFractions :: Integer -> Int
 nbFractions d = foldl' (+) 0 (map (traceShowId . length . reducedProper . traceShowId) [2..d])
 
+solutionSlow = nbFractions 1000000
+
 -- Write a list of all factors
 factors = concatMap (\(x,n) -> replicate n x) . factorise
 
@@ -52,10 +54,4 @@ phi n
       | otherwise = (a - 1) * prodPhi (b:t)
 
 -- less than 5s
-solution n = sum $ map phi [2..n]
-
-main :: IO ()
-main = do
-  let n = 1000000
-  -- print $ nbFractions n -- 303963552391
-  print $ solution n
+solution = let n = 1000000 in sum $ map phi [2..n]