Here's another freebie, but I am not really sure how to solve it. Guess I wouldn't be getting that job at Google :)
This problem was asked by Google.
The area of a circle is defined as πr^2. Estimate π to 3 decimal places using a Monte Carlo method.
Hint: The basic equation of a circle is x2 + y2 = r2.
c++ solution
@Absinthe Even worse overengineering than previously: https://gitlab.com/tymorl/warmups/blob/master/MCPie/sol.cpp .
I think the most interesting part is the stopping condition. I arrived at it by a mix of trial-and-error and intuition. The intuition was just "the square is needed, because something something statistics", so pretty bad. If anyone knows what the stopping condition should be I am all ears.
c++ solution
@Absinthe But then how many points should I add between checks whether it calmed down? If I add only one point, then it "calms down" as soon as I generated about 1k points, which is much too early. Although maybe I'm missing something.