CF/SRM's mouth record.

　　Feel the whole bzoj do not have a future, a few Uncle Gan SRM, I will open a pit to mouth Hu Yipo cf/srm in order to quickly roll thick. (because it is the mouth of the Hu do not set the counter, in fact, I am lazy.)

"SRM645" easy to sort by the sorting line directly to sweep it again.

"SRM645" Medium if the direction vector of each point is the same then it may be able to reach otherwise certainly not. ① If even step, there are two kinds of vector synthesis, we can use extended gcd to determine whether it is feasible. ② if it is an odd step, just run one step, then follow the ① to do it.

CF/SRM's mouth record.