added implementation for heap sort algorithm

arijit-pande · arijit-pande · commit 04d15692a8df · 2016-08-14T09:51:52.000Z
diff --git a/sorts/heap_sort.py b/sorts/heap_sort.py
@@ -0,0 +1,35 @@
+def heapify(unsorted,index,heap_size):
+	largest = index
+	left_index = 2*index + 1
+	right_index = 2*index + 2
+	if left_index < heap_size and unsorted[left_index] > unsorted[largest]:
+		largest = left_index
+	
+	if right_index < heap_size and unsorted[right_index] > unsorted[largest]:
+		largest = right_index
+
+	if largest != index:
+		unsorted[largest],unsorted[index] = unsorted[index],unsorted[largest]
+		heapify(unsorted,largest,heap_size)		
+		
+def heap_sort(unsorted):	
+	n=len(unsorted) 
+	for i in range (n/2 - 1 , -1, -1) :
+		heapify(unsorted,i,n)
+	for i in range(n - 1, -1, -1):
+		unsorted[0], unsorted[i] = unsorted[i], unsorted[0]
+		heapify(unsorted,0,i)
+	return unsorted
+
+
+if __name__ == '__main__':
+ import sys
+ if sys.version_info.major < 3:
+ input_function = raw_input
+ else:
+ input_function = input
+
+ user_input = input_function('Enter numbers separated by coma:\n')
+ unsorted = [int(item) for item in user_input.split(',')]
+ print heap_sort(unsorted)
+

-Original file line number
+Diff line change
@@ @@ -0,0 +1,35 @@ @@
 +defheapify(unsorted,index,heap_size):
 +largest=index
 +left_index=2*index+1
 +right_index=2*index+2
 +ifleft_index<heap_sizeandunsorted[left_index] >unsorted[largest]:
 +largest=left_index
++
 +ifright_index<heap_sizeandunsorted[right_index] >unsorted[largest]:
 +largest=right_index
++
 +iflargest!=index:
 +unsorted[largest],unsorted[index] =unsorted[index],unsorted[largest]
 +heapify(unsorted,largest,heap_size)
++
 +defheap_sort(unsorted):
 +n=len(unsorted)
 +foriinrange (n/2-1 , -1, -1) :
 +heapify(unsorted,i,n)
 +foriinrange(n-1, -1, -1):
 +unsorted[0], unsorted[i] =unsorted[i], unsorted[0]
 +heapify(unsorted,0,i)
 +returnunsorted
++
++
 +if__name__=='__main__':
 +importsys
 +ifsys.version_info.major<3:
 +input_function=raw_input
 +else:
 +input_function=input
++
 +user_input=input_function('Enter numbers separated by coma:\n')
 +unsorted= [int(item) foriteminuser_input.split(',')]
 +printheap_sort(unsorted)
++