第一次写的解法，，。对于只有一个儿子的节点重复了两次 。。结果就弄复杂了。。我也觉得不应该能有这么多的重复嘛
<span style="font-size:18px;">/** * Definition for binary tree * public class TreeNode { *int val; *TreeNode left; *TreeNode right; *TreeNode(int x) { val = x; } * } */ package javaTrain;public class Train9 {public int sum = 0;public int sumNumbers(TreeNode root) {if(root == null) return sum;sum = dfs(root.left,root.val)+dfs(root.right,root.val);return sum;}private int dfs(TreeNode root,int num){if(root == null) return num;return dfs(root.left,num*10+root.val) + dfs(root.right,num*10+root.val);}}</span>
调整后的正解，唉~边界要想清楚呀。。
<span style="font-size:18px;">/** * Definition for binary tree * public class TreeNode { *int val; *TreeNode left; *TreeNode right; *TreeNode(int x) { val = x; } * } */public class Solution {public int sumNumbers(TreeNode root) {return helper(root,0);}private int helper(TreeNode root, int sum){if(root == null)return 0;if(root.left==null && root.right==null)return sum*10+root.val;return helper(root.left,sum*10+root.val)+helper(root.right,sum*10+root.val);}}</span>
人生没有彩排，只有现场直播，所以每一件事都要努力做得最好
