feat: added shell sort in Python

Author: leitao

basic/sorting/ShellSort/ShellSort.py

@@ -0,0 +1,15 @@
+def shellSort(arr):
+    n = len(arr)
+    gap = int(n/2)
+    while gap > 0:
+        for i in range(gap,n):
+            temp = arr[i]
+            j = i
+            while  j >= gap and arr[j-gap] >temp:
+                arr[j] = arr[j-gap]
+                j -= gap
+            arr[j] = temp
+        gap = int(gap/2)
+
+arr = [ 12, 34, 54, 2, 3]
+shellSort(arr)