A supplemental book: <a href = "http://opendatastructures.org/ods-python.pdf">book</a><br>
A Big-O Chart: <a href = "https://www.bigocheatsheet.com/">chart</a><br>
BST simulator: <a href = "https://www.cs.usfca.edu/~galles/visualization/BST.html">here</a><br>
2-3 Tree simulator: <a href = "https://www.cs.usfca.edu/~galles/visualization/BTree.html">here</a><br>
Other simulators: <a href = "https://visualgo.net/en/">here</a><br>
Python Code simulator: <a href = "https://pythontutor.com/">here</a><br>