2023

Day 4

Python list.index() will give the location of the first occurence of an element in a list. It can be useful for getting the part of a list before and after a certain marker
Python list.count(a) will count occurences of a in the list
[1,2,3]*3 will evaluate to [1,2,3,1,2,3,1,2,3]
frozenset is a hashable but immutable type of set. In other words, frozenset can not be modified after creation but can be used for e.g. dict keys
math.gcd(*args) for greatest divisor and math.lcm(*args) for least common multiple
math.prod(iterable). No need for np.prod and works on all iterables