What are you talking about? There's a lot of expressions like O(n + k), O(n * k) or O(n * log k) in typical algorithm books (CLRS certainly has them). There's n

What are you talking about? There's a lot of expressions like O(n + k), O(n * k) or O(n * log k) in typical algorithm books (CLRS certainly has them). There's nothing special about O(n - k).