题解 | #牛群的最长距离#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    int n = 0;
    int inorder(TreeNode* root)
    {
        if (root == nullptr)
            return 0;
        int l = inorder(root->left);
        int r = inorder(root->right);
        n = max(n, l + r);
        return max(l, r) + 1;
    }
    int diameterOfBinaryTree(TreeNode* root) {
        // write code here
        inorder(root);
        return n;
    }
};