/// https://leetcode.com/problems/diameter-of-binary-tree/
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    
    int height(TreeNode* root){
        if(root==NULL){
            return 0;
        }
        return 1 + max(height(root->left), height(root->right));
    }
    
    int diameterOfBinaryTree(TreeNode* root) {
        if(root==NULL){
            return 0;
        }
        int option1 = height(root->left) + height(root->right);
        int option2 = diameterOfBinaryTree(root->left);
        int option3 = diameterOfBinaryTree(root->right);
        
        return max(option1, max(option2, option3));
    }
};