Merge pull request #24 from MacBox7/heap-sort

Thanks for contribution

heap_sort.rb

@@ -0,0 +1,34 @@
+"""
+Algorithm: Heap-Sort
+Time-Complexity: O(nlogn)
+"""
+def heap_sort(array)  
+    array_size = array.size  
+    adjusted_array = [nil] + array            
+    (array_size / 2).downto(1) do |i|  
+        adjusted_down(adjusted_array, i, array_size)  
+    end  
+    while array_size > 1  
+        adjusted_array[1], adjusted_array[array_size] = adjusted_array[array_size], adjusted_array[1]  
+        array_size -= 1  
+        adjusted_down(adjusted_array, 1, array_size)  
+    end  
+    adjusted_array.drop(1)                  
+ end  
+
+#Method to adjust heap in downward manner
+def adjusted_down(adjusted_array, parent, limit)  
+    top = adjusted_array[parent]  
+    while (child = 2 * parent) <= limit  
+        child += 1  if child < limit and adjusted_array[child] < adjusted_array[child + 1]  
+        break  if top >= adjusted_array[child]  
+        adjusted_array[parent] = adjusted_array[child]  
+        parent = child  
+    end  
+    adjusted_array[parent] = top  
+end  
+
+
+#Code for testing heapsort
+array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15].shuffle
+print heap_sort(array)