Merge pull request #16 from fiuskylab/feat/associative-array

Add associative array data structure

array/associative/README.md

@@ -0,0 +1,6 @@
+# Associative Array
+
+## Useful Links
+- [Associative Array](https://en.wikipedia.org/wiki/Associative_array)
+- [Hash Table](https://en.wikipedia.org/wiki/Hash_table)
+- [Search Tree](https://en.wikipedia.org/wiki/Search_tree)

array/associative/associative.go

@@ -0,0 +1,59 @@
+package associative
+
+type (
+	// Array - Associative Array (aka Map) is a key-value
+	// data structure.
+	Array[K comparable, T any] struct {
+		items []item[K, T]
+	}
+
+	item[K comparable, T any] struct {
+		Key   K
+		Value *T
+	}
+)
+
+// NewArray returns a associative array instance.
+func NewArray[K comparable, T any]() *Array[K, T] {
+	return &Array[K, T]{
+		items: []item[K, T]{},
+	}
+}
+
+// Put adds an item to current Associative Array.
+func (a *Array[K, T]) Put(key K, value T) {
+	a.items = append(a.items, item[K, T]{
+		Key:   key,
+		Value: &value,
+	})
+}
+
+// Get retrieves an item associated with given Key,
+// currently O(n).
+func (a *Array[K, T]) Get(key K) *T {
+	for _, i := range a.items {
+		if i.Key == key {
+			return i.Value
+		}
+	}
+
+	return nil
+}
+
+// Delete removes an item from Associative Array, returns:
+// 	- true: if item was found
+// 	- false: if item wasn't found
+func (a *Array[K, T]) Delete(key K) bool {
+	for p, i := range a.items {
+		if i.Key == key {
+			if p == 0 {
+				a.items = a.items[p:]
+				return true
+			}
+			a.items = append(a.items[:p], a.items[p-1:]...)
+			return true
+		}
+	}
+
+	return false
+}

array/associative/associative_test.go

@@ -0,0 +1,70 @@
+package associative
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNew(t *testing.T) {
+	require := require.New(t)
+
+	m := NewArray[int, string]()
+
+	require.NotNil(m)
+	require.NotNil(m.items)
+}
+
+func TestPut(t *testing.T) {
+	require := require.New(t)
+	m := NewArray[int, string]()
+
+	expectedValue := "um"
+	m.Put(1, expectedValue)
+
+	require.NotNil(m.items[0].Value)
+	require.Equal(*m.items[0].Value, expectedValue)
+}
+
+func TestGet(t *testing.T) {
+	m := NewArray[int, string]()
+
+	t.Run("Empty Array", func(t *testing.T) {
+		require := require.New(t)
+
+		require.Nil(m.Get(1))
+	})
+
+	t.Run("With item", func(t *testing.T) {
+		m.Put(1, "um")
+		t.Run("Wrong key", func(t *testing.T) {
+			require := require.New(t)
+
+			require.Nil(m.Get(2))
+		})
+
+		t.Run("Found", func(t *testing.T) {
+			require := require.New(t)
+
+			require.NotNil(m.Get(1))
+		})
+	})
+}
+
+func TestDelete(t *testing.T) {
+	m := NewArray[int, string]()
+
+	m.Put(1, "um")
+
+	t.Run("Wrong Key", func(t *testing.T) {
+		require := require.New(t)
+
+		require.False(m.Delete(20))
+	})
+
+	t.Run("Found", func(t *testing.T) {
+		require := require.New(t)
+
+		require.True(m.Delete(1))
+	})
+}