No, I mean O(2^n). O(2^n) includes everything that grows slower than 2^n as well. It is no relation to the worst case performance of merge sort, just a clarification on the definition of Big O.
> Big O specifically describes the worst-case scenario, and can be used to describe the execution time required or the space used (e.g. in memory or on disk) by an algorithm.
From higher up in the article. You picked the O(N) section description to pick a nit with the whole article when it covers exactly what you want it to earlier.
