From 4538b95ee864bcd2c07de34b67d7ccdef21eb4fb Mon Sep 17 00:00:00 2001
From: bygu4 <sacha05bugaev@gmail.com>
Date: Thu, 10 Apr 2025 16:55:28 +0300
Subject: [PATCH 1/4] add first two tasks solutions

---
 Tasks/Test/Test.Tests/BinaryTreeTests.fs      | 31 +++++++++++++++++++
 .../Test/Test.Tests/InfiniteSequenceTests.fs  | 20 ++++++++++++
 Tasks/Test/Test.Tests/Program.fs              |  4 +++
 Tasks/Test/Test.Tests/Test.Tests.fsproj       | 30 ++++++++++++++++++
 Tasks/Test/Test.sln                           | 28 +++++++++++++++++
 Tasks/Test/Test/BinaryTree.fs                 | 21 +++++++++++++
 Tasks/Test/Test/InfiniteSequence.fs           | 14 +++++++++
 Tasks/Test/Test/PriorityQueue.fs              | 12 +++++++
 Tasks/Test/Test/Test.fsproj                   | 14 +++++++++
 9 files changed, 174 insertions(+)
 create mode 100644 Tasks/Test/Test.Tests/BinaryTreeTests.fs
 create mode 100644 Tasks/Test/Test.Tests/InfiniteSequenceTests.fs
 create mode 100644 Tasks/Test/Test.Tests/Program.fs
 create mode 100644 Tasks/Test/Test.Tests/Test.Tests.fsproj
 create mode 100644 Tasks/Test/Test.sln
 create mode 100644 Tasks/Test/Test/BinaryTree.fs
 create mode 100644 Tasks/Test/Test/InfiniteSequence.fs
 create mode 100644 Tasks/Test/Test/PriorityQueue.fs
 create mode 100644 Tasks/Test/Test/Test.fsproj

diff --git a/Tasks/Test/Test.Tests/BinaryTreeTests.fs b/Tasks/Test/Test.Tests/BinaryTreeTests.fs
new file mode 100644
index 0000000..b91fe4b
--- /dev/null
+++ b/Tasks/Test/Test.Tests/BinaryTreeTests.fs
@@ -0,0 +1,31 @@
+module BinaryTree.Tests
+
+open NUnit.Framework
+open FsUnit
+
+[<Test>]
+let testFilter_EmptyTree_GetEmptyList () =
+    filter None (fun x -> x > 0) |> _.IsEmpty |> should be True
+
+[<Test>]
+let testFilter_SingleElementTree_GetTheTip () =
+    filter (Tip ("abc", None, None)) (fun s -> s.StartsWith "a")
+    |> should equal ["abc"]
+
+[<Test>]
+let testFilter_NestedTree_GetEvenNumbers () =
+    let tree = Tip (100,
+        Tip (0,
+            Tip (-1,
+                None,
+                Tip (15, None, None)
+                ),
+            Tip (-124, None, None)
+            ),
+        Tip (1000,
+            Tip (-6, None, None),
+            None
+            )
+        )
+    filter tree (fun x -> x % 2 = 0)
+    |> should equal [0; -124; 100; -6; 1000]
diff --git a/Tasks/Test/Test.Tests/InfiniteSequenceTests.fs b/Tasks/Test/Test.Tests/InfiniteSequenceTests.fs
new file mode 100644
index 0000000..2a6c889
--- /dev/null
+++ b/Tasks/Test/Test.Tests/InfiniteSequenceTests.fs
@@ -0,0 +1,20 @@
+module InfiniteSequence.Tests
+
+open NUnit.Framework
+open FsUnit
+open FsCheck
+open FsCheck.NUnit
+
+[<Property>]
+let anyEvenIndexOfSequenceIsPositive (index: NonNegativeInt) =
+    match index with
+    | x when int x % 2 = 0 -> Seq.item (int x) signAlternatingSequence > 0
+    | x -> Seq.item (int x) signAlternatingSequence < 0
+
+[<Test>]
+let testSequence_GetFirstNItems () =
+    signAlternatingSequence
+    |> Seq.take 12
+    |> should equal (seq [1; -2; 3; -4; 5; -6; 7; -8; 9; -10; 11; -12])
+
+Check.QuickThrowOnFailure anyEvenIndexOfSequenceIsPositive
diff --git a/Tasks/Test/Test.Tests/Program.fs b/Tasks/Test/Test.Tests/Program.fs
new file mode 100644
index 0000000..96b133f
--- /dev/null
+++ b/Tasks/Test/Test.Tests/Program.fs
@@ -0,0 +1,4 @@
+module Program
+
+[<EntryPoint>]
+let main _ = 0
diff --git a/Tasks/Test/Test.Tests/Test.Tests.fsproj b/Tasks/Test/Test.Tests/Test.Tests.fsproj
new file mode 100644
index 0000000..eb4dcae
--- /dev/null
+++ b/Tasks/Test/Test.Tests/Test.Tests.fsproj
@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <IsPackable>false</IsPackable>
+    <GenerateProgramFile>false</GenerateProgramFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="BinaryTreeTests.fs" />
+    <Compile Include="InfiniteSequenceTests.fs" />
+    <Compile Include="Program.fs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="Fscheck.nunit" Version="3.1.0" />
+    <PackageReference Include="fsunit" Version="7.0.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="NUnit" Version="4.2.2" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.4.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Test\Test.fsproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/Tasks/Test/Test.sln b/Tasks/Test/Test.sln
new file mode 100644
index 0000000..9edec8e
--- /dev/null
+++ b/Tasks/Test/Test.sln
@@ -0,0 +1,28 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31903.59
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "Test", "Test\Test.fsproj", "{A1E410C5-287A-40C7-833F-34021FFB093A}"
+EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "Test.Tests", "Test.Tests\Test.Tests.fsproj", "{0BA19CC2-24D0-45D5-A373-30698C147C27}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{A1E410C5-287A-40C7-833F-34021FFB093A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A1E410C5-287A-40C7-833F-34021FFB093A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A1E410C5-287A-40C7-833F-34021FFB093A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A1E410C5-287A-40C7-833F-34021FFB093A}.Release|Any CPU.Build.0 = Release|Any CPU
+		{0BA19CC2-24D0-45D5-A373-30698C147C27}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{0BA19CC2-24D0-45D5-A373-30698C147C27}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{0BA19CC2-24D0-45D5-A373-30698C147C27}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{0BA19CC2-24D0-45D5-A373-30698C147C27}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal
diff --git a/Tasks/Test/Test/BinaryTree.fs b/Tasks/Test/Test/BinaryTree.fs
new file mode 100644
index 0000000..ffbdfd9
--- /dev/null
+++ b/Tasks/Test/Test/BinaryTree.fs
@@ -0,0 +1,21 @@
+module BinaryTree
+
+type Tree<'a> =
+    | None
+    | Tip of 'a * Tree<'a> * Tree<'a>
+
+let filter (tree: Tree<'a>) (condition: 'a -> bool) =
+    let rec filterInternal (tree: Tree<'a>) (condition: 'a -> bool) (cont: unit -> 'a list) =
+        match tree with
+        | None -> cont ()
+        | Tip (x, left, right) ->
+            if condition x then
+                filterInternal left condition (fun () ->
+                    x :: filterInternal right condition cont
+                )
+            else
+                filterInternal left condition (fun () ->
+                    filterInternal right condition cont
+                )
+
+    filterInternal tree condition (fun () -> [])
diff --git a/Tasks/Test/Test/InfiniteSequence.fs b/Tasks/Test/Test/InfiniteSequence.fs
new file mode 100644
index 0000000..fc6ae3f
--- /dev/null
+++ b/Tasks/Test/Test/InfiniteSequence.fs
@@ -0,0 +1,14 @@
+module InfiniteSequence
+
+let signAlternatingOnes =
+    Seq.initInfinite (( + ) 1)
+    |> Seq.map (fun x ->
+        match x with
+        | x when x % 2 = 0 -> -1
+        | _ -> 1
+    )
+
+let signAlternatingSequence =
+    Seq.initInfinite (( + ) 1)
+    |> Seq.zip signAlternatingOnes
+    |> Seq.map (fun (x, y) -> x * y)
diff --git a/Tasks/Test/Test/PriorityQueue.fs b/Tasks/Test/Test/PriorityQueue.fs
new file mode 100644
index 0000000..250a797
--- /dev/null
+++ b/Tasks/Test/Test/PriorityQueue.fs
@@ -0,0 +1,12 @@
+module PriorityQueue
+
+open System
+
+type Queue<'a>() =
+    let mutable elements: ('a * int) list = []
+
+    member _.Enqueue (element: 'a, priority: int) =
+        elements <- (element, priority) :: elements
+
+    member _.Dequeue () =
+        if elements.IsEmpty then raise (new InvalidOperationException "queue was empty")
diff --git a/Tasks/Test/Test/Test.fsproj b/Tasks/Test/Test/Test.fsproj
new file mode 100644
index 0000000..43d0645
--- /dev/null
+++ b/Tasks/Test/Test/Test.fsproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="BinaryTree.fs" />
+    <Compile Include="InfiniteSequence.fs" />
+    <Compile Include="PriorityQueue.fs" />
+  </ItemGroup>
+
+</Project>

From 4335cc47b19fda69eab05e32b268f8ba19baf61b Mon Sep 17 00:00:00 2001
From: bygu4 <sacha05bugaev@gmail.com>
Date: Thu, 10 Apr 2025 17:00:29 +0300
Subject: [PATCH 2/4] add comments

---
 Tasks/Test/Test/BinaryTree.fs       |  4 ++++
 Tasks/Test/Test/InfiniteSequence.fs |  4 ++++
 Tasks/Test/Test/PriorityQueue.fs    | 12 ------------
 Tasks/Test/Test/Test.fsproj         |  1 -
 4 files changed, 8 insertions(+), 13 deletions(-)
 delete mode 100644 Tasks/Test/Test/PriorityQueue.fs

diff --git a/Tasks/Test/Test/BinaryTree.fs b/Tasks/Test/Test/BinaryTree.fs
index ffbdfd9..f110914 100644
--- a/Tasks/Test/Test/BinaryTree.fs
+++ b/Tasks/Test/Test/BinaryTree.fs
@@ -1,10 +1,14 @@
 module BinaryTree
 
+/// Definition of a binary tree.
 type Tree<'a> =
     | None
     | Tip of 'a * Tree<'a> * Tree<'a>
 
+/// Get of the elements of the given  `tree` for which the `condition` is true.
 let filter (tree: Tree<'a>) (condition: 'a -> bool) =
+
+    /// Traverse the `tree` in CPS style.
     let rec filterInternal (tree: Tree<'a>) (condition: 'a -> bool) (cont: unit -> 'a list) =
         match tree with
         | None -> cont ()
diff --git a/Tasks/Test/Test/InfiniteSequence.fs b/Tasks/Test/Test/InfiniteSequence.fs
index fc6ae3f..058bb36 100644
--- a/Tasks/Test/Test/InfiniteSequence.fs
+++ b/Tasks/Test/Test/InfiniteSequence.fs
@@ -1,5 +1,7 @@
 module InfiniteSequence
 
+/// A sign alternating sequence of ones.
+/// (1, -1, 1, -1, ...)
 let signAlternatingOnes =
     Seq.initInfinite (( + ) 1)
     |> Seq.map (fun x ->
@@ -8,6 +10,8 @@ let signAlternatingOnes =
         | _ -> 1
     )
 
+/// A sign alternating sequence with ascending module.
+/// (1, -2, 3, -4, ...)
 let signAlternatingSequence =
     Seq.initInfinite (( + ) 1)
     |> Seq.zip signAlternatingOnes
diff --git a/Tasks/Test/Test/PriorityQueue.fs b/Tasks/Test/Test/PriorityQueue.fs
deleted file mode 100644
index 250a797..0000000
--- a/Tasks/Test/Test/PriorityQueue.fs
+++ /dev/null
@@ -1,12 +0,0 @@
-module PriorityQueue
-
-open System
-
-type Queue<'a>() =
-    let mutable elements: ('a * int) list = []
-
-    member _.Enqueue (element: 'a, priority: int) =
-        elements <- (element, priority) :: elements
-
-    member _.Dequeue () =
-        if elements.IsEmpty then raise (new InvalidOperationException "queue was empty")
diff --git a/Tasks/Test/Test/Test.fsproj b/Tasks/Test/Test/Test.fsproj
index 43d0645..f47966e 100644
--- a/Tasks/Test/Test/Test.fsproj
+++ b/Tasks/Test/Test/Test.fsproj
@@ -8,7 +8,6 @@
   <ItemGroup>
     <Compile Include="BinaryTree.fs" />
     <Compile Include="InfiniteSequence.fs" />
-    <Compile Include="PriorityQueue.fs" />
   </ItemGroup>
 
 </Project>

From 891931ae8b6ccae182421e785c38a65041337db2 Mon Sep 17 00:00:00 2001
From: bygu4 <sacha05bugaev@gmail.com>
Date: Thu, 10 Apr 2025 17:00:59 +0300
Subject: [PATCH 3/4] correct comment

---
 Tasks/Test/Test/BinaryTree.fs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tasks/Test/Test/BinaryTree.fs b/Tasks/Test/Test/BinaryTree.fs
index f110914..98b65a4 100644
--- a/Tasks/Test/Test/BinaryTree.fs
+++ b/Tasks/Test/Test/BinaryTree.fs
@@ -8,7 +8,7 @@ type Tree<'a> =
 /// Get of the elements of the given  `tree` for which the `condition` is true.
 let filter (tree: Tree<'a>) (condition: 'a -> bool) =
 
-    /// Traverse the `tree` in CPS style.
+    /// Traverse the `tree` in CPS.
     let rec filterInternal (tree: Tree<'a>) (condition: 'a -> bool) (cont: unit -> 'a list) =
         match tree with
         | None -> cont ()

From 370bdc0862da53ee57b66454ad0f4912f8d561e6 Mon Sep 17 00:00:00 2001
From: bygu4 <sacha05bugaev@gmail.com>
Date: Thu, 10 Apr 2025 17:23:26 +0300
Subject: [PATCH 4/4] correct typo

---
 Tasks/Test/Test/BinaryTree.fs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tasks/Test/Test/BinaryTree.fs b/Tasks/Test/Test/BinaryTree.fs
index 98b65a4..b662979 100644
--- a/Tasks/Test/Test/BinaryTree.fs
+++ b/Tasks/Test/Test/BinaryTree.fs
@@ -5,7 +5,7 @@ type Tree<'a> =
     | None
     | Tip of 'a * Tree<'a> * Tree<'a>
 
-/// Get of the elements of the given  `tree` for which the `condition` is true.
+/// Get all of the elements of the given `tree` for which the `condition` is true.
 let filter (tree: Tree<'a>) (condition: 'a -> bool) =
 
     /// Traverse the `tree` in CPS.