I would like to know if there is any way to retrieve previously submitted solutions and edit them from the interview coding challenges. Thanks.
Short answer: only for the projects.
Long answer: There are two different types of saved progress for Free Code Camp: your profile and your browser cache.
A list of your completed challenges is saved to your account in the FCC database. You can see the list of completed challenges by looking at your public portfolio. With a growing curriculum already over 1,400 lessons and a growing user base several times that size, FCC does not store every solution to ever challenge in its database. There are some challenges which are classified as projects required for certifications. Your solutions to those can be viewed on your settings page.
Your in-editor code is saved in your browser’s local storage. Recent in-progress code from the challenge editor is also saved in your local browser cache when you run tests. Because FCC rolled out a completely new application, the old cached values are no longer valid. This is the same effect you would have if you cleared your browser cache. If you are completing lessons and do not see your recent code, then something is preventing FCC from writing to your browser’s storage. This could be a browser setting, a privacy extension, or a browser version incompatibility. Especially as you get to more complicated challenges that may take multiple sessions, I strongly recommend saving your in-progress work outside of the browser cache.
This is a good opportunity to learn the ins and outs of your GitHub account, but you can also just save locally or use a service like repl.it which allows for versioning. The FCC team is working on creating an easy way for campers to download a solution when a challenge is completed. You can help add useful tools like this by being a contributor .