How do I implement a graph in Java?

How do I implement a graph in Java?

You can implement a graph in Java using an adjacency list or an adjacency matrix. Which one would you prefer?

I think an adjacency list would be better. Can you show me an example?

Sure! Here's a simple implementation using an adjacency list:

import java.util.*;

class Graph {
    private Map<Integer, List<Integer>> adjList;

    public Graph() {
        adjList = new HashMap<>();
    }

    public void addVertex(int vertex) {
        adjList.putIfAbsent(vertex, new ArrayList<>());
    }

    public void addEdge(int source, int destination) {
        adjList.get(source).add(destination);
        adjList.get(destination).add(source); // For undirected graph
    }
}

That looks good! How do I traverse this graph?

You can use Depth-First Search (DFS) or Breadth-First Search (BFS) for traversal. Would you like an example of one of these?