Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results.

Note: The input string may contain letters other than the parentheses ( and ).

Example 1:

Input: "()())()"

Output: ["()()()", "(())()"]

Example 2:

Input: "(a)())()"

Output: ["(a)()()", "(a())()"]

Example 3:

Input: ")("

Output: [""]

Given a reference of a node in a connected undirected graph, return a deep copy (clone) of the graph. Each node in the graph contains a val (int) and a list (List[Node]) of its neighbors.

Example:

Input: {"$id":"1","neighbors":[{"$id":"2","neighbors":[{"$ref":"1"},{"$id":"3","neighbors":[{"$ref":"2"},{"$id":"4","neighbors":[{"$ref":"3"},{"$ref":"1"}],"val":4}],"val":3}],"val":2},{"$ref":"4"}],"val":1}

Explanation:

Node 1's value is 1, and it has two neighbors: Node 2 and 4.

Node 2's value is 2, and it has two neighbors: Node 1 and 3.

Node 3's value is 3, and it has two neighbors: Node 2 and 4.

Node 4's value is 4, and it has two neighbors: Node 1 and 3.

Note:

The number of nodes will be between 1 and 100.

The undirected graph is a simple graph, which means no repeated edges and no self-loops in the graph.

Since the graph is undirected, if node p has node q as neighbor, then node q must have node p as neighbor too.

You must return the copy of the given node as a reference to the cloned graph.