We say that an algorithm is O(f(n)) if the number of simple operations that the computer has to do eventually less that the constant time f(n), as n increases.

• f(n) could be linear (f(n) = n)
• f(n) could be quadratic (f(n) = n^2)
• f(n) could be constant (f(n) = 1)
• f(n) could be something entirely different!