mtry

摘要： American HeritageFarmer John takes the heritage of his cows very seriously. He is not, however, a truly fine bookkeeper. He keeps his cow genealogies as binary trees and, instead of writing them in graphic form, he records them in the more linear `tree in-order' and `tree pre-order' notation 阅读全文

摘要： Electric FenceDon PieleIn this problem, `lattice points' in the plane are points with integer coordinates.In order to contain his cows, Farmer John constructs a triangular electric fence by stringing a "hot" wire from the origin (0,0) to a lattice point [n,m] (0<=;n<32000, 0<m 阅读全文