TreeNode* increasingBST(TreeNode* root) {

         if (root == NULL)

             return NULL;

         vector<int> v;

         inorder(root,v);

         TreeNode* dummy = new TreeNode();

         TreeNode *p = dummy;

         for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {

             TreeNode *tmp = new TreeNode(*it);

             p->right = tmp;

             p = p->right;

         }

         return dummy->right;

     }

     void inorder(TreeNode *root, vector<int> &v)

     {

         if (root == NULL)

             return ;

         inorder(root->left, v);

         v.push_back(root->val);

         inorder(root->right,v);

     }