919. 完全二叉树插入器 https://leetcode.cn/problems/complete-binary-tree-inserter
919. Complete Binary Tree Inserter https://leetcode.com/problems/complete-binary-tree-inserter
872. 叶子相似的树 https://leetcode.cn/problems/leaf-similar-trees
872. Leaf-Similar Trees https://leetcode.com/problems/leaf-similar-trees
863. 二叉树中所有距离为 K 的结点 https://leetcode.cn/problems/all-nodes-distance-k-in-binary-tree
863. All Nodes Distance K in Binary Tree https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree
有些二叉树的特殊题型需要用层序遍历的方式来做，比如下面列举的几道题。这类问题你就当开阔眼界有个印象就行了，不会有太多变体。
