Merge pull request geekcomputers#1063 from mohd-mehraj/patch-6

Shell Sort

Author: geekcomputers

Sorting Algorithims/Shell Sort

@@ -0,0 +1,47 @@
+# Python program for implementation of Shell Sort 
+
+def shellSort(arr): 
+
+	# Start with a big gap, then reduce the gap 
+	n = len(arr) 
+	gap = n/2
+
+	# Do a gapped insertion sort for this gap size. 
+	# The first gap elements a[0..gap-1] are already in gapped 
+	# order keep adding one more element until the entire array 
+	# is gap sorted 
+	while gap > 0: 
+
+		for i in range(gap,n): 
+
+			# add a[i] to the elements that have been gap sorted 
+			# save a[i] in temp and make a hole at position i 
+			temp = arr[i] 
+
+			# shift earlier gap-sorted elements up until the correct 
+			# location for a[i] is found 
+			j = i 
+			while j >= gap and arr[j-gap] >temp: 
+				arr[j] = arr[j-gap] 
+				j -= gap 
+
+			# put temp (the original a[i]) in its correct location 
+			arr[j] = temp 
+		gap /= 2
+
+
+# Driver code to test above 
+arr = [ 12, 34, 54, 2, 3] 
+
+n = len(arr) 
+print ("Array before sorting:") 
+for i in range(n): 
+	print(arr[i]), 
+
+shellSort(arr) 
+
+print ("\nArray after sorting:") 
+for i in range(n): 
+	print(arr[i]), 
+
+# This code is contributed by mohd-mehraj