Implement hash set

hash_set/hash_set/hash_set.go

@@ -0,0 +1,92 @@
+package hash_set
+
+import (
+	"fmt"
+	"strings"
+)
+
+type MyHash interface {
+	~string | ~int | ~uint | ~int64 | ~uint64 | ~int32 | ~uint32 | ~int16 | ~uint16 | ~int8 | ~uint8
+}
+
+type Hasher[H MyHash] interface {
+	Hash() H
+}
+
+// MyHashSet is a hash set implementation.
+type MyHashSet[T Hasher[H], H MyHash] struct {
+	storage map[H]T
+}
+
+// NewSet initializes a new hash set.
+func NewSet[T Hasher[H], H MyHash]() MyHashSet[T, H] {
+	return MyHashSet[T, H]{
+		storage: make(map[H]T, 100),
+	}
+}
+
+// Add adds an element to a set.
+func (s *MyHashSet[T, H]) Add(element T) {
+	// Hash element
+	hash := element.Hash()
+
+	// Save
+	_, ok := s.storage[hash]
+	if !ok {
+		s.storage[hash] = element
+	}
+}
+
+// AddAll adds all the elements to the set.
+func (s *MyHashSet[T, H]) AddAll(elements ...T) {
+	for _, element := range elements {
+		s.Add(element)
+	}
+}
+
+// Contains checks if the hash set contains the element T.
+// Returns true if the element is part of the set, false otherwise.
+func (s *MyHashSet[T, H]) Contains(element T) bool {
+	// Hash element
+	hash := element.Hash()
+	_, ok := s.storage[hash]
+	return ok
+}
+
+// Delete deletes an element from the set.
+// Returns true if the element was deleted, false otherwise.
+func (s *MyHashSet[T, H]) Delete(element T) bool {
+	// Hash element
+	hash := element.Hash()
+	_, ok := s.storage[hash]
+	if ok {
+		delete(s.storage, hash)
+		return true
+	}
+	return false
+}
+
+// String returns the string representation of the set.
+func (s *MyHashSet[T, H]) String() string {
+	var sb strings.Builder
+	sb.WriteString("MyHashSet{")
+	for _, value := range s.storage {
+		sb.WriteString(fmt.Sprintf("%v,", value))
+	}
+	sb.WriteString("}")
+	return sb.String()
+}
+
+// Union creates a union of two sets
+func (s *MyHashSet[T, H]) Union(other *MyHashSet[T, H]) {
+	for _, v := range other.storage {
+		s.Add(v)
+	}
+}
+
+// Sub creates a difference of two sets
+func (s *MyHashSet[T, H]) Sub(other *MyHashSet[T, H]) {
+	for _, v := range other.storage {
+		s.Delete(v)
+	}
+}

hash_set/hash_set/hash_set_test.go

@@ -0,0 +1,85 @@
+package hash_set
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+type MyString struct {
+	Value string
+}
+
+func (m MyString) Hash() string {
+	return m.Value
+}
+
+func TestNewSet(t *testing.T) {
+	newSet := NewSet[MyString, string]()
+	assert.NotNil(t, newSet)
+}
+
+func TestMyHashSet_Add(t *testing.T) {
+	// Given
+	newSet := NewSet[MyString, string]()
+	newSet.Add(MyString{Value: "some"})
+
+	// Then
+	assert.True(t, newSet.Contains(MyString{Value: "some"}))
+}
+
+func TestMyHashSet_AddAll(t *testing.T) {
+	// Given
+	newSet := NewSet[MyString, string]()
+	newSet.AddAll(MyString{Value: "some"}, MyString{Value: "another"})
+
+	// Then
+	assert.True(t, newSet.Contains(MyString{Value: "some"}))
+	assert.True(t, newSet.Contains(MyString{Value: "another"}))
+}
+
+func TestMyHashSet_Delete(t *testing.T) {
+	// Given
+	newSet := NewSet[MyString, string]()
+	newSet.AddAll(MyString{Value: "some"}, MyString{Value: "another"})
+	newSet.Delete(MyString{Value: "some"})
+
+	// Then
+	assert.False(t, newSet.Contains(MyString{Value: "some"}))
+	assert.True(t, newSet.Contains(MyString{Value: "another"}))
+}
+
+func TestMyHashSet_Union(t *testing.T) {
+	// Setup
+	newSet := NewSet[MyString, string]()
+	newSet.AddAll(MyString{Value: "some"}, MyString{Value: "another"})
+
+	anotherSet := NewSet[MyString, string]()
+	anotherSet.AddAll(MyString{Value: "Batman"}, MyString{Value: "Robin"})
+
+	// Test
+	newSet.Union(&anotherSet)
+
+	// Then
+	assert.True(t, newSet.Contains(MyString{Value: "some"}))
+	assert.True(t, newSet.Contains(MyString{Value: "another"}))
+	assert.True(t, newSet.Contains(MyString{Value: "Batman"}))
+	assert.True(t, newSet.Contains(MyString{Value: "Robin"}))
+}
+
+func TestMyHashSet_Sub(t *testing.T) {
+	// Setup
+	newSet := NewSet[MyString, string]()
+	newSet.AddAll(MyString{Value: "some"}, MyString{Value: "another"}, MyString{Value: "Batman"})
+
+	anotherSet := NewSet[MyString, string]()
+	anotherSet.AddAll(MyString{Value: "Batman"}, MyString{Value: "Robin"})
+
+	// Test
+	newSet.Sub(&anotherSet)
+
+	// Then
+	assert.True(t, newSet.Contains(MyString{Value: "some"}))
+	assert.True(t, newSet.Contains(MyString{Value: "another"}))
+	assert.False(t, newSet.Contains(MyString{Value: "Batman"}))
+	assert.False(t, newSet.Contains(MyString{Value: "Robin"}))
+}

hash_set/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+	"go-dsa/hash_set/v2/hash_set"
+)
+
+type Person struct {
+	Name string
+	Age  int
+}
+
+// Hash returns the has of a person, it conforms to the hash_set.Hasher interface
+func (p Person) Hash() string {
+	return fmt.Sprintf("%s-%d", p.Name, p.Age)
+}
+
+func main() {
+	mySet := hash_set.NewSet[Person, string]()
+
+	// Add
+	mySet.Add(Person{
+		Name: "Batman",
+		Age:  28,
+	})
+	mySet.Add(Person{
+		Name: "Robin",
+		Age:  16,
+	})
+	mySet.Add(Person{
+		Name: "Batman",
+		Age:  28,
+	})
+
+	// Print
+	fmt.Printf("%s\n", mySet.String())
+
+	// Contains
+	result := mySet.Contains(Person{
+		Name: "Batman",
+		Age:  28,
+	})
+	fmt.Printf("Set contains batman %v\n", result)
+
+	// Deletion
+	mySet.Delete(Person{
+		Name: "Batman",
+		Age:  28,
+	})
+	fmt.Printf("%s\n", mySet.String())
+}

main.go

@@ -1,25 +0,0 @@
-package main
-
-import (
-  "fmt"
-)
-
-//TIP To run your code, right-click the code and select <b>Run</b>. Alternatively, click
-// the <icon src="AllIcons.Actions.Execute"/> icon in the gutter and select the <b>Run</b> menu item from here.
-
-func main() {
-  //TIP Press <shortcut actionId="ShowIntentionActions"/> when your caret is at the underlined or highlighted text
-  // to see how GoLand suggests fixing it.
-  s := "gopher"
-  fmt.Println("Hello and welcome, %s!", s)
-
-  for i := 1; i <= 5; i++ {
-	//TIP You can try debugging your code. We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
-	// for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>. To start your debugging session, 
-	// right-click your code in the editor and select the <b>Debug</b> option. 
-	fmt.Println("i =", 100/i)
-  }
-}
-
-//TIP See GoLand help at <a href="https://www.jetbrains.com/help/go/">jetbrains.com/help/go/</a>.
-// Also, you can try interactive lessons for GoLand by selecting 'Help | Learn IDE Features' from the main menu.

readme.md

@@ -0,0 +1,6 @@
+# Data Structures and Algorithms
+
+This repository is my self study guide for data structures and algorithms. I implement them from scratch in Go
+and then write unit test for them.
+
+What better way to learn a language and new concepts exists other than practicing them.