Since this book is paired with cses.fi, more string algorithms should be mentioned (Aho Corasick, string automaton, KMP)

As far as I can tell, knowledge of something like Aho Corasick or string automaton is necessary to solve some of these problems like "Finding Patterns" , "Counting Patterns", etc. Also, "String Functions" wants us to use KMP's prefix function but it's not mentioned in the book.