1, 543. Diameter of Binary Tree 维护左右子树的高度,同时更新结果,返回以该节点结束的最大长度.递归调用. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Sol…