Dwylkz

Obviously, it's kind of LCA problem. I assume that you guys have already learned about LCA stuff :). So I just talk about the main idea of my method. Our goal is to connect three specific node by u

/* Three operations L : the same as input, correspond to Preorder traversal. b x : correspond to ask how many sons does x's father have. c x y : LCA(x, y), there is a trick, if LCA(x, y)