Digit dp introduction:
USACO gold problem that uses this:
This is late, but I wrote a book about DP (https://dp-book.com/) which has a detailed explanation of Digit DP in addition to the solution to Count the Cows, as coconut mentioned.
This can probably be added to the guide
Sheesh… Where did you find time to write that? We should add this to the guide lol (p good ngl)…
It looks cool!