data structures
https://en.wikipedia.org/wiki/Primitive_data_type
https://en.wikipedia.org/wiki/Abstract_data_type
https://en.wikipedia.org/wiki/Data_structure
https://www.cs.auckland.ac.nz/software/AlgAnim/ds_ToC.html
https://www.geeksforgeeks.org/introduction-to-data-structures
https://www.geeksforgeeks.org/advanced-data-structures
algorithms
https://www.w3schools.com/dsa/index.php
https://www.tutorialspoint.com/data_structures_algorithms/index.htm
https://techdevguide.withgoogle.com/paths/data-structures-and-algorithms/
https://www.programiz.com/dsa
https://www.geeksforgeeks.org/learn-data-structures-and-algorithms-dsa-tutorial
https://www.geeksforgeeks.org/must-do-coding-questions-for-companies-like-amazon-microsoft-adobe