Ln (x) dx · 2016-03-31 16:53:52

I simulated the moves of balls and what really happens when they move. And at some spesific period of time (for example each 0.01 seconds) i calculated the new position of all balls.

But don'y know what i'm missing?
I get wrong answer, and when decrease time period get TLE!
In problem statements what exactly the second estcase is? It has 3 balls or 4?

Help!