You are given a tree,and each node have a number on it.You have to find some nodes a1,a2,a3 ... ,an such a2 is child of a1 ,a3 is child of a2,...an is child of an - 1.We say x is child of y if it's in subtree with root in y. This problem was on Serbian state competition 2014. for seniors,could you give me any hints or pseudocode?