问题
How to find the Big O for the following recursive function using the recursive method:
T(n)=(n-1)T(n-1)+(n-1)T(n-2)
回答1:
Anyway, I tried to solve this case using the classic recursive relation methodology. It's all about observing if a pattern exists:
Very expensive algorithm (Enemies of computer science are factorial and exponential orders of growth).
来源：https://stackoverflow.com/questions/24362452/big-o-notation-using-the-recursion-method