Which algorithm is used by string::find in c++?

Question

I need to search for a sub-string in a given string. C++ provides library function 'find' for this. What is the algorithm used by this library function? For purpose of competitive programming, should I use this function or use KMP search algorithm?

Answer 1

With a quick search, I found this:

• KMP is O(n + k)
• Find is O(n * k)

So KMP is a faster search algorithm.

C++ string::find complexity

Knuth–Morris–Pratt algorithm