sliding-window: update todos in readme

algorithms/dynamic/sliding-window/README.md

@@ -4,8 +4,17 @@ publish this as article at root url: sliding-window/
 
 definition
 
-link to YT vid
+link to YT vid & qd article
 
 link pseudo code
 
 list problem links
+
+python versions
+
+// use below in readme TOC and comments on .js/.py files
+•	Difficulty 1: Statically Sized Sliding Window: Find maximum (or minimum) sum subarray of desired size in a given array.
+•	Difficulty 2: Dynamically Sized Sliding Window: Given an array of positive integers, find the contiguous subarray of integers that add up to a given number.
+o	Variation: Same question but for an array with all integers (positive, 0, negative). The optimum solution is Kadane's Algorithm, but the sliding window technique is still ok.
+•	Strings: Given a string and n letters, find the shortest substring that contains all given letters.
+•	Flipping/Swapping: Find the maximum sequence of continuous 1's that can be formed by replacing at-most k 0's by 1's.