Hi! I found a type of problems I couldn't solve, but I read that we can solve them using FFT or generating functions. I don't know how to use these approaches here, can someone help me please? (I didn't found a tutorial, just discussions) The problems are: - Square Grid - The last problem in this note of Petr's blog - Kalel, The Jumping Frog Would be nice for me a more detailed explanation or a resource to check