Merge pull request tulika-99#55 from DGKSK8LIFE/master

Create HeapSort.go

Author: tulika-99

Heap Sort/HeapSort.go

@@ -0,0 +1,55 @@
+package main
+
+import "fmt"
+
+type MaxHeap struct {
+    slice    []int
+    heapSize int
+}
+
+func BuildMaxHeap(slice []int) MaxHeap {
+    h := MaxHeap{slice: slice, heapSize: len(slice)}
+    for i := len(slice) / 2; i >= 0; i-- {
+        h.MaxHeapify(i)
+    }
+    return h
+}
+
+func (h MaxHeap) MaxHeapify(i int) {
+    l, r := 2*i+1, 2*i+2
+    max := i
+
+    if l < h.size() && h.slice[l] > h.slice[max] {
+        max = l
+    }
+    if r < h.size() && h.slice[r] > h.slice[max] {
+        max = r
+    }
+    //log.Printf("MaxHeapify(%v): l,r=%v,%v; max=%v\t%v\n", i, l, r, max, h.slice)
+    if max != i {
+        h.slice[i], h.slice[max] = h.slice[max], h.slice[i]
+        h.MaxHeapify(max)
+    }
+}
+
+func (h MaxHeap) size() int { return h.heapSize } // ???
+
+func heapSort(slice []int) []int {
+    h := BuildMaxHeap(slice)
+    //log.Println(slice)
+    for i := len(h.slice) - 1; i >= 1; i-- {
+        h.slice[0], h.slice[i] = h.slice[i], h.slice[0]
+        h.heapSize--
+        h.MaxHeapify(0)
+    }
+    return h.slice
+}
+
+func main() {
+    s := []int{4, 1, 3, 2, 16, 9, 10, 14, 8, 7}
+    h := BuildMaxHeap(s)
+    fmt.Println(h)
+
+    s = heapSort(s)
+    fmt.Println(s)
+}