思路:dfs,当找到叶子节点后,把叶子节点的值加入到字符串中,再把字符串转为整型加入到和中。 public class Solution { int s=0; public int sumNumbers (TreeNode root) { // write code here sum(root,""); return s; } public void sum(TreeNode node,String str){ if(node!=null){ str=st...