[ch-074/jeongoon] add Elm Solution

4 files changed, 190 insertions, 0 deletions

diff --git a/challenge-074/jeongoon/elm/elm.json b/challenge-074/jeongoon/elm/elm.json
new file mode 100644
index 0000000000..dea3450db1
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+++ b/challenge-074/jeongoon/elm/elm.json
@@ -0,0 +1,24 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/browser": "1.0.2",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0"
+        },
+        "indirect": {
+            "elm/json": "1.1.3",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.2"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}
diff --git a/challenge-074/jeongoon/elm/src/Ch1.elm b/challenge-074/jeongoon/elm/src/Ch1.elm
new file mode 100644
index 0000000000..b66343e505
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+++ b/challenge-074/jeongoon/elm/src/Ch1.elm
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+module Ch1 exposing (pairNumberListAndMajor)
+import String
+import Tuple
+import List exposing (map, head, tail)
+
+pairNumberListAndMajor : String -> ( List Int, Maybe Int )
+pairNumberListAndMajor newListString =
+    let newNumberList = List.filterMap
+                        String.toInt (String.split " " newListString)
+        count k = List.length( List.filter (\y -> k == y) newNumberList )
+        halfLen = List.length( newNumberList ) // 2 -- //-> integer division
+        findMajor maybels  =
+            case maybels of
+                Nothing -> Nothing
+                Just ls ->
+                    case (List.head ls) of
+                        Nothing -> Nothing
+                        Just  m -> if (count m) > halfLen
+                                   then Just m
+                                   else findMajor (List.tail ls)
+    in
+        ( newNumberList, findMajor (Just newNumberList) )
diff --git a/challenge-074/jeongoon/elm/src/Ch2.elm b/challenge-074/jeongoon/elm/src/Ch2.elm
new file mode 100644
index 0000000000..4a0f1c3768
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+++ b/challenge-074/jeongoon/elm/src/Ch2.elm
@@ -0,0 +1,38 @@
+module Ch2 exposing (getFNR)
+import String exposing (join, split)
+import Dict
+import List exposing (head, tail)
+import Maybe exposing (withDefault)
+
+getFNR : String -> Maybe String
+getFNR newString =
+    let chrs   = split "" newString
+        counts x dic = case (Dict.get x dic) of
+                         Nothing -> 0
+                         Just  n -> n
+        doFind dic rfnr cs =
+            case (head cs) of
+                Nothing ->
+                    if List.length rfnr == 0 then Nothing
+                    else Just (join "" (List.reverse rfnr))
+                Just  k ->
+                    case (counts k dic) of
+                             0 -> doFind (Dict.insert k 1 dic) (k :: rfnr)
+                                      (withDefault [] (tail cs))
+                             m -> doFind (Dict.insert k (m+1) dic)
+                                      ((findPrevious
+                                            (Dict.insert k (m+1) dic) rfnr)
+                                                :: rfnr)
+                                      (withDefault [] (tail cs))
+        findPrevious dic nrs =
+            case (head nrs) of
+                Nothing -> "#"
+                Just  y ->
+                    case (Dict.get y dic) of
+                        Nothing -> y
+                        Just  u -> if u == 1 then y
+                                   else findPrevious dic
+                                       (withDefault [] (tail nrs))
+
+    in
+        doFind Dict.empty [] chrs
diff --git a/challenge-074/jeongoon/elm/src/Main.elm b/challenge-074/jeongoon/elm/src/Main.elm
new file mode 100644
index 0000000000..936a00d7a4
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+++ b/challenge-074/jeongoon/elm/src/Main.elm
@@ -0,0 +1,106 @@
+{- Tested with:
+elm make src/Main.elm
+# and access elm/index.html in a web browser(firefox in my case)
+# which shows Task1 and Task2 altogether: couldn't find the better way
+-}
+
+module Main exposing (..)
+import Browser
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import Html.Events exposing (onInput)
+
+import String
+import List exposing (map, head, tail)
+
+import Ch1
+import Ch2
+
+-- MAIN
+
+main =
+  Browser.sandbox { init = init, update = update, view = view }
+
+-- MODEL
+
+type alias Model =
+  { numberListString : String
+  , numberList : List Int
+  , majorNumber : Maybe Int
+  , charListString : String
+  , fnrString : Maybe String
+  }
+
+init : Model
+init =
+  Model "" [] Nothing "" Nothing
+
+-- UPDATE
+
+type Msg
+  = FindMajor String
+  | GetFNR String
+
+update : Msg -> Model -> Model
+update msg model =
+
+  case msg of
+    FindMajor newListString ->
+        let result = Ch1.pairNumberListAndMajor newListString
+        in { model
+               | numberListString = newListString,
+                 numberList  = Tuple.first  result,
+                 majorNumber = Tuple.second result }
+    GetFNR newString ->
+        { model
+            | charListString = newString,
+              fnrString      = if String.length newString == 0 then Nothing
+                               else Ch2.getFNR newString }
+
+
+-- VIEW
+
+view : Model -> Html Msg
+view model =
+  div [ style "width" "90%" ]
+      [ h1 [] [ text "Task1: Majority Element" ]
+      , viewInput "text" "Type List of numbers, separated by space"
+          model.numberListString FindMajor
+      , displaySizeOfList model
+      , displayMajor model
+      , h1 [] [ text "Task2: FNR" ]
+      , viewInput "text" "Type a string consists of characters"
+          model.charListString GetFNR
+      , displayFNR model
+      ]
+
+
+viewInput : String -> String -> String -> (String -> msg) -> Html msg
+viewInput t p v toMsg =
+  div [ style "background-color" "gray" ]
+      [ input [ size 150, type_ t, placeholder p, value v, onInput toMsg ] [] ]
+
+displaySizeOfList : Model -> Html msg
+displaySizeOfList model =
+    case (List.length model.numberList) of
+        0 -> div [] [ text "Size: 0" ]
+        x -> div [] [ text ( "Size: " ++ (String.fromInt x) ) ]
+
+displayMajor : Model -> Html msg
+displayMajor model =
+    case model.majorNumber of
+        Nothing ->
+            if List.length model.numberList == 0 then
+                div [ style "color" "blue" ] [ text "List is empty" ]
+            else
+                div [ style "color" "red" ] [ text "Major Not Found: -1" ]
+        Just  x ->
+            div [ style "color" "green" ] [ text ( "Major Number: " ++
+                                                       String.fromInt(x) ) ]
+
+displayFNR model =
+    case model.fnrString of
+        Nothing ->
+            div [ style "color" "red" ] [ text "No String given" ]
+        Just  s ->
+            div [ style "color" "green" ] [ text s ]