void dfs( Node *root,vector<int>&list)
{
    if( root==NULL )
    {
        list.push_back(-1);
        return;
    }


    list.push_back( root->data );

    dfs( root->left );
    dfs( root->right );
}

vector<int> serialize(Node *root)
{

    vector<int>list;

    dfs( root,list );

    //5  3 -1 -1 2 6 -1 -1 1 -1 -1

    return list;
}


void totree( Node* root,int &pos,vector<int>&list )
{

    if( list[pos]==-1 )
    {
        pos++;
        return;
    }

    root= new Node();
    root->data=list[pos];

    pos++;
    totree( root->left,pos,list );
    totree( root->right,pos,list );

}

Node *deserialize(vector<int> list)
{


    Node *root;
    root=NULL;
    //5  3 -1 -1 2 6 -1 -1 1 -1 -1
    totree( root,0,list );


}