Firstly, the phrase "weird" I use is for problems that have a solution where you can't really prove the time complexity with real proof but rather with intuition, estimation... For example problem 2284C2, (I'm not sure if there's any other ways to solve but from many sources they all have the same idea as mine) the solution for k = 2 is to brute force to find the value c that gcd(a, c) = gcd(b, c) = 1. It is said that c will be found after approximately 300 steps which I have no idea why. Can anyone explain the boundary 300 steps in the problem and are there any tips to recognize and solve these weird problems?