lab 6 task 7

lab6/Makefile

@@ -1,4 +1,4 @@
-.PHONY: run build clean task1 build-task1 clean-task1 task2 build-task2 clean-task2 task3 build-task3 clean-task3 task4 build-task4 clean-task4 task5 build-task5 clean-task5 task6 build-task6 clean-task6
+.PHONY: run build clean task1 build-task1 clean-task1 task2 build-task2 clean-task2 task3 build-task3 clean-task3 task4 build-task4 clean-task4 task5 build-task5 clean-task5 task6 build-task6 clean-task6 task7 build-task7 clean-task7
 
 # task1
 run:
@@ -71,3 +71,13 @@ build-task6:
 
 clean-task6:
 	cd task6 && dotnet clean
+
+# task7
+task7:
+	cd task7 && dotnet run --project task7.fsproj
+
+build-task7:
+	cd task7 && dotnet build
+
+clean-task7:
+	cd task7 && dotnet clean

lab6/task7/Program.fs

@@ -0,0 +1,128 @@
+module Task7
+
+open System
+open System.Collections.Generic
+
+let countFrequencies (lst: 'a list) : ('a * int) list when 'a : equality =
+    lst
+    |> List.groupBy id
+    |> List.map (fun (key, group) -> (key, List.length group))
+
+let findMostFrequent (lst: 'a list) : 'a option when 'a : equality =
+    if List.isEmpty lst then
+        None
+    else
+        lst
+        |> countFrequencies
+        |> List.maxBy snd
+        |> fst
+        |> Some
+
+let findMostFrequentWithCount (lst: 'a list) : ('a * int) option when 'a : equality =
+    if List.isEmpty lst then
+        None
+    else
+        lst
+        |> countFrequencies
+        |> List.maxBy snd
+        |> Some
+
+let findAllMostFrequent (lst: 'a list) : 'a list when 'a : equality =
+    if List.isEmpty lst then
+        []
+    else
+        let frequencies = countFrequencies lst
+        let maxCount = frequencies |> List.map snd |> List.max
+        frequencies
+        |> List.filter (fun (_, count) -> count = maxCount)
+        |> List.map fst
+
+let getFrequencyStats (lst: 'a list) : Map<'a, int> when 'a : comparison =
+    lst
+    |> List.groupBy id
+    |> List.map (fun (key, group) -> (key, List.length group))
+    |> Map.ofList
+
+let findLeastFrequent (lst: 'a list) : 'a option when 'a : equality =
+    if List.isEmpty lst then
+        None
+    else
+        lst
+        |> countFrequencies
+        |> List.minBy snd
+        |> fst
+        |> Some
+
+let filterByFrequency (minCount: int) (lst: 'a list) : 'a list when 'a : equality =
+    let frequencies = countFrequencies lst
+    frequencies
+    |> List.filter (fun (_, count) -> count >= minCount)
+    |> List.collect (fun (element, count) -> List.replicate count element)
+
+let getUniqueElements (lst: 'a list) : 'a list when 'a : equality =
+    lst
+    |> countFrequencies
+    |> List.filter (fun (_, count) -> count = 1)
+    |> List.map fst
+
+let removeDuplicates (lst: 'a list) : 'a list when 'a : equality =
+    lst |> List.distinct
+
+let sortByFrequency (ascending: bool) (lst: 'a list) : ('a * int) list when 'a : equality =
+    let frequencies = countFrequencies lst
+    if ascending then
+        frequencies |> List.sortBy snd
+    else
+        frequencies |> List.sortByDescending snd
+
+[<EntryPoint>]
+let main argv =
+    let testList1 = [1; 2; 3; 2; 4; 2; 5; 3; 2]
+    printfn "Test list 1: %A" testList1
+    
+    match findMostFrequent testList1 with
+    | Some element -> printfn "Most frequent element: %A" element
+    | None -> printfn "Empty list"
+    
+    match findMostFrequentWithCount testList1 with
+    | Some (element, count) -> printfn "Most frequent: %A appears %d times" element count
+    | None -> printfn "Empty list"
+    
+    let frequencies1 = countFrequencies testList1
+    printfn "All frequencies: %A" frequencies1
+    
+    let testList2 = ["apple"; "banana"; "apple"; "cherry"; "banana"; "apple"]
+    printfn "\nTest list 2: %A" testList2
+    
+    match findMostFrequent testList2 with
+    | Some element -> printfn "Most frequent string: %A" element
+    | None -> printfn "Empty list"
+    
+    let allMostFrequent = findAllMostFrequent [1; 2; 2; 3; 3]
+    printfn "\nAll most frequent in [1; 2; 2; 3; 3]: %A" allMostFrequent
+    
+    let stats = getFrequencyStats testList1
+    printfn "\nFrequency stats: %A" stats
+    
+    match findLeastFrequent testList1 with
+    | Some element -> printfn "Least frequent element: %A" element
+    | None -> printfn "Empty list"
+    
+    let filtered = filterByFrequency 2 testList1
+    printfn "Elements appearing at least 2 times: %A" filtered
+    
+    let unique = getUniqueElements testList1
+    printfn "Unique elements (appearing once): %A" unique
+    
+    let noDuplicates = removeDuplicates testList1
+    printfn "List without duplicates: %A" noDuplicates
+    
+    let sortedByFreq = sortByFrequency false testList1
+    printfn "Sorted by frequency (descending): %A" sortedByFreq
+    
+    let emptyList = []
+    match findMostFrequent emptyList with
+    | Some element -> printfn "Should not happen: %A" element
+    | None -> printfn "\nEmpty list handled correctly"
+    
+    0

lab6/task7/task7.fsproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>