Added HeapSort to the deck

HeapSort/HeapSort.go

@@ -0,0 +1,50 @@
+package HeapSort
+
+type Heap struct {
+}
+
+func (heap *Heap) HeapSort(array []int) {
+	heap.BuildHeap(array)
+
+	for length:= len(array); length > 1; length-- {
+		heap.RemoveTop(array, length)
+	}
+}
+
+func (heap *Heap) BuildHeap(array []int) {
+	for i := len(array) / 2; i >= 0; i-- {
+		heap.Heapify(array, i, len(array))
+	}
+}
+
+func (heap *Heap) RemoveTop(array []int, length int) {
+	var lastIndex = length - 1
+	array[0], array[lastIndex] = array[lastIndex], array[0]
+	heap.Heapify(array, 0, lastIndex)
+}
+
+func (heap *Heap) Heapify(array []int, root, length int) {
+	var max = root
+	var l, r = heap.Left(array, root), heap.Right(array, root)
+
+	if l < length && array[l] > array[max] {
+		max = l
+	}
+
+	if r < length && array[r] > array[max] {
+		max = r
+	}
+
+	if max != root {
+		array[root], array[max] = array[max], array[root]
+		heap.Heapify(array, max, length)
+	}
+}
+
+func (*Heap) Left(array []int, root int) int {
+	return (root * 2) + 1
+}
+
+func (*Heap) Right(array []int, root int) int {
+	return (root * 2) + 2
+}

HeapSort/HeapSort_test.go

@@ -0,0 +1,26 @@
+package HeapSort
+
+import (
+	"math/rand"
+	"sort"
+	"testing"
+	"time"
+)
+
+func TestHeapSort(t *testing.T) {
+	random := rand.New(rand.NewSource(time.Now().UnixNano()))
+	array1 := make([]int, random.Intn(100-10)+10)
+	for i := range array1 {
+		array1[i] = random.Intn(100)
+	}
+	array2 := make(sort.IntSlice, len(array1))
+	copy(array2, array1)
+	var heap = new(Heap)
+	heap.HeapSort(array1)
+	array2.Sort()
+	for i := range array1 {
+		if array1[i] != array2[i] {
+			t.Fail()
+		}
+	}
+}

README.md

@@ -39,6 +39,7 @@ There are several data structures and algorithms implemented in this project. Th
 - Cocktail Sort
 - Gnome Sort
 - Merge Sort
+- Heap Sort
 
 ## Usage