Is there a difference between statement "Worst case running time of an Algorithm A" and "Running time of an Algorithm A is O(n)"?
What I think "there is no difference" because, worst case is the peak running time that the function can take, O(n) means that the function is "bounded by". Both give the same meaning.
Hope my logic is correct.
There is difference.
An algorithm is O(f) is not precise: you must say an alogirthm is O(f) in its best/worst/avarage case. You can say that is O(f) when best, worst and avarage are the same, but that's not so common.