Class Solution


  • public class Solution
    extends Object
    133 - Clone Graph\. Medium Given a reference of a node in a **[connected](https://en.wikipedia.org/wiki/Connectivity_(graph_theory)#Connected_graph)** undirected graph. Return a [**deep copy** ](https://en.wikipedia.org/wiki/Object_copying#Deep_copy) (clone) of the graph. Each node in the graph contains a value (`int`) and a list (`List[Node]`) of its neighbors. class Node { public int val; public List neighbors; } **Test case format:** For simplicity, each node's value is the same as the node's index (1-indexed). For example, the first node with `val == 1`, the second node with `val == 2`, and so on. The graph is represented in the test case using an adjacency list. **An adjacency list** is a collection of unordered **lists** used to represent a finite graph. Each list describes the set of neighbors of a node in the graph. The given node will always be the first node with `val = 1`. You must return the **copy of the given node** as a reference to the cloned graph. **Example 1:** ![](https://assets.leetcode.com/uploads/2019/11/04/133_clone_graph_question.png) **Input:** adjList = \[\[2,4],[1,3],[2,4],[1,3]] **Output:** [[2,4],[1,3],[2,4],[1,3]] **Explanation:** There are 4 nodes in the graph. 1st node (val = 1)'s neighbors are 2nd node (val = 2) and 4th node (val = 4). 2nd node (val = 2)'s neighbors are 1st node (val = 1) and 3rd node (val = 3). 3rd node (val = 3)'s neighbors are 2nd node (val = 2) and 4th node (val = 4). 4th node (val = 4)'s neighbors are 1st node (val = 1) and 3rd node (val = 3). **Example 2:** ![](https://assets.leetcode.com/uploads/2020/01/07/graph.png) **Input:** adjList = \[\[]] **Output:** [ []] **Explanation:** Note that the input contains one empty list. The graph consists of only one node with val = 1 and it does not have any neighbors. **Example 3:** **Input:** adjList = [] **Output:** [] **Explanation:** This an empty graph, it does not have any nodes. **Example 4:** ![](https://assets.leetcode.com/uploads/2020/01/07/graph-1.png) **Input:** adjList = \[\[2],[1]] **Output:** [[2],[1]] **Constraints:** * The number of nodes in the graph is in the range `[0, 100]`. * `1 <= Node.val <= 100` * `Node.val` is unique for each node. * There are no repeated edges and no self-loops in the graph. * The Graph is connected and all nodes can be visited starting from the given node.
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • cloneGraph

        public Node cloneGraph​(Node node)