Tangentially related, but I like how readable the source code of CPython (the official interpreter for Python) is. It is plain C without many shenanigans. If you wonder how Python handles big integer, hashmaps, and so on, just dive in the source code!

A few days ago, I wanted a concrete example about dynamic arrays. The examples in computer science textbook always uses a factor of 2 when expanding, since it is very convenient to demonstrate that it gives an amortized O(1) insertion time. Some people find it wasteful, and may resort to use a constant expansion (e.g. 128) instead, leading to a O(n / 128), i.e. O(n) insertion time instead.

But you can just make the expansion factor less than 2. I wanted a concrete example, so, naturally, I just went for CPython's implementation of `list`. It took me less than 2 minutes to find it: https://github.com/python/cpython/blob/main/Objects/listobje....

If you're curious, CPython essentially grows its dynamic array by ⅛ (12.5%) whenever it needs to.