标签：Plan child nts NPU lan therefore inpu null val
Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path 1->2->3 which represents the number 123.
Find the total sum of all root-to-leaf numbers.
Note: A leaf is a node with no children.
Example:
Input: [1,2,3]
1
/ 2 3
Output: 25
Explanation:
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Therefore, sum = 12 + 13 = 25.
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { int res = 0; public int sumNumbers(TreeNode root) { helper(root, 0); return res; } private void helper(TreeNode root, int sum) { if (root == null) { return; } int curSum = 10 * sum + root.val; if (root.left == null && root.right == null) { res += curSum; } helper(root.left, curSum); helper(root.right, curSum); } }
[LC] 129. Sum Root to Leaf Numbers
标签：Plan child nts NPU lan therefore inpu null val
原文地址：https://www.cnblogs.com/xuanlu/p/12028384.html
