Count on a Treap

In computer science, a treap is a binary search tree according to the keys and meanwhile a heap according to the weights. Follow the link for more details: http://en.wikipedia.org/wiki/Treap Your task is to maintain a max-treap supporting the following operations: - 0 k w: Insert a new node, whose key and weight are k and w. - 1 k: Delete a node in the treap with key k. - 2 ku kv: Return the d