/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int diameterOfBinaryTree(TreeNode* root) {
if(root == NULL) return 0;
int left = getDepth(root->left);
int right = getDepth(root->right);
return max(left+right,max(diameterOfBinaryTree(root->left),diameterOfBinaryTree(root->right)));
}
int getDepth(TreeNode* root){
if(root == NULL) return 0;
int left = getDepth(root->left);
int right = getDepth(root->right);
return max(left,right)+1;
}
};