/**
 * 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 largeheight(TreeNode* root)
    {
        if(!root) return 0;
        return max(largeheight(root->left), largeheight(root->right))+1;
    }

    int diameterOfBinaryTree(TreeNode* root) {
        if(!root) return 0;
        int h1=largeheight(root->left);
        int h2=largeheight(root->right);
        int p1=h1+h2;
        return max(p1, max(diameterOfBinaryTree(root->left), diameterOfBinaryTree(root->right)));
    }
};