Medium
Quiz
#133 Clone Graph
APPROACH
Given a reference to one node in a connected, undirected graph, return a complete deep copy of the graph.
Each node stores an integer value (int) and a list of its neighbors (List[Node]):
class Node {
public int val;
public List neighbors;
}
Test case format:
For convenience, each node's value equals its 1-based index. The graph is described as an adjacency list.
An adjacency list is a collection of unordered lists describing each node's neighbors.
The input node always has val = 1. Return the matching node in the cloned graph.
Example 1:
class Node {
public int val;
public List<Node> neighbors;
}
Example 2:
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 3:
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 4:
Input: adjList = []
Output: []
Explanation: This an empty graph, it does not have any nodes.
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What is the optimal approach for this problem?