Math definition goes something like this: f(n)=O(g(n)), if exists C such that f(n) < C x g(n), when n goes to infinity.

Function “quickSortExecutionTime(permutation)” depends on exact input (each permutation/shuffle has different exec time), parameter “permutation” can not go to infinity, so it can’t be used with O(n) directly. (Parameter need to be single real number)

QuickSortWorstCaseTime(n) is single valued function thus, it can be used with O(n) notation. Same is true for quickSortAvgCaseTime(n) and quickSortBestCaseTime(n).

But you answered my question. (Very indirect “Yes” :) )