归档 2015年8月16日

题目描述：

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.

For example:

Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return ...

题目描述：

Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

   1
 /   \
2     3
 \
  5

All root-to-leaf paths are:

["1->2->5", "1->3"]

题目大意：

给定一棵二叉树，返回所有“根到叶子”的路径。

例如，给定下面的二叉树：

   1
 /   \
2     3
 \
  5

所有“根到叶子”路径为：

["1->2->5", "1->3"]

解题思路：

树的遍历 ...