Maximum Depth of Binary Tree

 int maxDepth(TreeNode *root) 
 {
     if(root == NULL)
     {
         return 0;
     }   
 
     int leftDepth = maxDepth(root->left);
 
     int rightDepth = maxDepth(root->right);
 
     if(leftDepth > rightDepth)
     {
         return leftDepth + 1;
     }
     else
     {
         return rightDepth + 1;
     }   
 }