Update README.md

Author: Bishal Sarangkoti

README.md

@@ -2,6 +2,14 @@
 
 Leetcode Questions Scrapper is a simple scrapper built on top of Selenium that fetches all the problems from leetcode and write as html and epub files.
 
+Although leetcode doesn't provide an official API to fetch all the list of problems, we can use the API url  [https://leetcode.com/api/problems/algorithms/](https://leetcode.com/api/problems/algorithms/) used by leetcode internally to fetch problems that returns a json file containing info about problems.
+The json file looks like this <br>
+![enter image description here](https://qph.fs.quoracdn.net/main-qimg-4ddf7b592d1a47df4385ffc714c215b7)<br>
+We can build links to each problem as 
+
+    “https://leetcode.com/problems/" + question_title_slug
+After getting the problem link we can fetch the content from the page using selenium (as Leetcode is built using react where content is rendered using JS we can't use lightweight library like requests).
+
 You can download the sample html and epub containing 11  problems [here](https://github.com/sarangbishal/Leetcode-Questions-Scrapper/tree/master/assets/sample%20output%20files).
 
 ## Requirements
@@ -23,7 +31,7 @@ Pip install all the requirements.
  - Run the following commands to download all algorithmic problems from leetcode
  `python main.py`
  ![enter image description here](https://raw.githubusercontent.com/sarangbishal/Leetcode-Questions-Scrapper/master/assets/screenshots/main.PNG?token=AG2ULFBE5HCEDG2FYTXPFW25RNWCU)
- <br>This downloads problem contents to 2 files: *****out.html***** and ***chapters.pickle***.
+ This downloads problem contents to 2 files: *****out.html***** and ***chapters.pickle***.
 
  **NOTE:** Leetcode may temporarily block requests. If the error occurs, wait for sometime and try again or use the proxy. Don't worry, Since, the previous state is saved to ***track.conf*** file, the download resumes from where it failed.