Algorithms

Data structures -> https://medium.com/coderbyte/how-to-get-good-at-algorithms-data-structures-d33d5163353f
Algorithms & data structures -> https://www.thealgorists.com/Algo
List of free ebooks -> https://github.com/EbookFoundation/free-programming-books
Book algorithms -> http://jeffe.cs.illinois.edu/teaching/algorithms/
Top coder -> https://www.topcoder.com/thrive/articles/Dynamic%20Programming:%20From%20Novice%20to%20Advanced
Tech with Google -> https://techdevguide.withgoogle.com/resources/?programming_languages=java&topics=interview-prep
Steven Skiena Algorithms -> https://www3.cs.stonybrook.edu/~skiena/373/videos/