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You are given an array pairs, where \(pairs[i] = [x_i, y_i]\), and:

• There are no duplicates.
• \(x_i < y_i\)

Let ways be the number of rooted trees that satisfy the following conditions:

• The tree consists of nodes whose values appeared in pairs.
• A pair \([x_i, y_i]\) exists in pairs if and only if \(x_i\) is an ancestor of \(y_i\) or \(y_i\) is an ancestor of \(x_i\).
• Note: the tree does not have to be a binary tree.

Two ways are considered to be different if there is at least one node that has different parents in both ways.

Return:

• 0 if ways == 0
• 1 if ways == 1
• 2 if ways > 1

A rooted tree is a tree that has a single root node, and all edges are oriented to be outgoing from the root.

An ancestor of a node is any node on the path from the root to that node (excluding the node itself). The root has no ancestors.

给出二叉 搜索 树的根节点，该树的节点值各不相同，请你将其转换为累加树（Greater Sum Tree），使每个节点 node  的新值等于原树中大于或等于  node.val  的值之和。