问题:
Given a binary tree containing digits from0-9only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path1->2->3which represents the number123.
Find the total sum of all root-to-leaf numbers.
For example,
1 / \ 2 3
The root-to-leaf path1->2represents the number12.
The root-to-leaf path1->3represents the number13.
Return the sum = 12 + 13 =25.
代码:
1 /** 2 * Definition for binary tree 3 * public class TreeNode { 4 * int val; 5 * TreeNode left; 6 * TreeNode right; 7 * TreeNode(int x) { val = x; } 8 * } 9 */ 10 public class Solution { 11 public int sumNumbers(TreeNode root) { 12 int sum = 0; 13 if(root==null) 14 return sum; 15 return sumNumbers(root,sum); 16 } 17 18 public int sumNumbers(TreeNode root, int sum){ 19 if(root==null) 20 return 0; 21 sum = sum*10+root.val; 22 if(root.left==null && root.right==null) 23 return sum; 24 return sumNumbers(root.left, sum) + sumNumbers(root.right, sum); 25 } 26 }