Adding URL for reference

Adding URL of sliding window technique for reference

Author: lydia321

data_structures/sliding_window/longest_substring_two_distinct.py

@@ -1,6 +1,7 @@
 def length_of_longest_substring_two_distinct(s):
     """
-    Finds the length of the longest substring with at most two distinct characters.
+    Finds the length of the longest substring with at most two distinct characters.[https://www.geeksforgeeks.org/window-sliding-technique/]
+
 
     Args:
     s (str): The input string.

data_structures/sliding_window/max_sum_subarray.py

@@ -1,6 +1,6 @@
 def max_sum_subarray(arr, k):
     """
-    Finds the maximum sum of a subarray of length k within the given array.
+    Finds the maximum sum of a subarray of length k within the given array.[https://www.geeksforgeeks.org/window-sliding-technique/]
 
     Args:
     arr (list): The input array.

data_structures/sliding_window/min_subarray_len.py

@@ -1,6 +1,7 @@
 def min_subarray_len(target, nums):
     """
-    Finds the minimal length of a contiguous subarray of which the sum is at least the target.
+    Finds the minimal length of a contiguous subarray of which the sum is at least the target.[https://www.geeksforgeeks.org/window-sliding-technique/]
+
 
     Args:
     target (int): The target sum.