Reputation: 115
To find their relation I substituted log n = x and log n! = n(log n)
so with base a , O( log n! )
became a^x(x)
and (log n)!
became x(x-1)(x-2)
....
now I think the first one has a higher growing speed. But can you help me to find their relation using big O of n^2
Upvotes: 2
Views: 2206
Reputation: 2908
Actually x(x-1)(x-2)....
becomes x^x + ...
because you have x
scopes. This means that O((log n)!)
has a higher growing speed.
Also, if log(n) := x
, then n = 2^x
and n^2
will become (2^x)^2 = 2^2x
which has lower growing speed than x^x
Summary
O(log n!) < O(n^2) < O((log n)!)
Upvotes: 1