Which algorithm is the fastest: O(n), O(ln), O(n^2)?

The fastest algorithm among those listed is O(ln) (logarithmic complexity).

Explanation of growth speed:

• O(ln n) grows the slowest as n increases.
• O(n) grows linearly with the size of the input data.
• O(n²) grows quadratically and becomes very slow for large n.

Example: for n=1000

• O(ln n) ≈ 6.9
• O(n) = 1000
• O(n²) = 1,000,000

Thus, O(ln) is the most efficient in terms of time among these three algorithms.