enh(Python): rename from insertionSort_rec to insertion_sort_rec (#669)

algorithms/Python/recursion/recursive_insertion_sort.py

@@ -4,17 +4,16 @@ Recursively sort first n-1 elements.
 Insert last element at its correct position in sorted array.
 """
 
-def insertionSort_rec(array, n):
-    # base case
-    if n <= 1:
+def insertion_sort_rec(array, length_arr):
+    """Base Case"""
+    if length_arr <= 1:
         return
     # Sort first n-1 elements
-    insertionSort_rec(array, n-1)
-    '''Insert last element at its correct position
-        in sorted array.'''
-    end = array[n-1]
-    j = n-2
-    
+    insertion_sort_rec(array, length_arr-1)
+    # Insert last element at its correct position in sorted array.
+    end = array[length_arr-1]
+    j = length_arr-2
+
     # Move elements of arr[0..i-1], that are
     # greater than key, to one position ahead
     # of their current position
@@ -23,8 +22,8 @@ def insertionSort_rec(array, n):
         j -= 1
     array[j+1] = end
 
-
-arr = [6, 5, 2, 7, 12, 9, 1, 4]
-insertionSort_rec(arr, len(arr))
-print("Sorted array is:")
-print(arr)
+if __name__ == '__main__':
+    arr = [6, 5, 2, 7, 12, 9, 1, 4]
+    insertion_sort_rec(arr, len(arr))
+    print("Sorted array is:")
+    print(arr)