559. N 叉树的最大深度 https://leetcode.cn/problems/maximum-depth-of-n-ary-tree
112. 路径总和 https://leetcode.cn/problems/path-sum
113. 路径总和 II https://leetcode.cn/problems/path-sum-ii
617. 合并二叉树 https://leetcode.cn/problems/merge-two-binary-trees
897. 递增顺序搜索树 https://leetcode.cn/problems/increasing-order-search-tree
938. 二叉搜索树的范围和 https://leetcode.cn/problems/range-sum-of-bst
1379. 找出克隆二叉树中的相同节点 https://leetcode.cn/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree
有的题目可以同时用「遍历」和「分解问题」两种思路来解，你可以利用这些题目训练自己的思维。