Python:
file reading and writing
string slicing, methods: .split(), .isdigit(), .strip(), .join()
list methods and functions: .sort() vs. sorted(), .append(), list()
dictionary methods and usage: key in dict
set methods and functions: set(), .add(), .pop()
Trees: know the structures of and how to create the classes for:
singly- and doubly-linked lists
binary trees
priority queues