import java.io.*; import java.util.*; public class Main { static class Node{ int value; Node left; Node right; public Node(int value) { this.value = value; } public Node(){ } } public static int countLongest (Node head, int k) { //key表示某个累加和,value表示这个累加和在路径中最早出现层数 HashMap<Integer, Integer> map...