I am aware that Java uses a Linear congruential generator. My question is- what is the complexity of generating a random number? How do you perform such analyses?

解决方案

The complexity of generating a random number is O(1). Do you mean "what are its costs in terms of runtime and memory"?

You can measure them with a micro-benchmark, e.g. junit-benchmark or Brent Boyer's Benchmark (see a larg list of such tools at What is the best macro-benchmarking tool / framework to measure a single-threaded complex algorithm in Java?).

Furthermore, I think Javas random number generators are quite fast, but statistically bad. Rather use external libraries, e.g. the Mersenne Twister at http://www.cs.gmu.edu/~sean/research/, or, if runtime is so important for you, the Fast Mersenne Twister.