Graph

// JavaScript Graph implementation (Adjacency List)
class Graph {
  constructor() {
    this.adjacencyList = {};
  }

  // Tilføj vertex
  addVertex(vertex) {
    if (!this.adjacencyList[vertex]) {
      this.adjacencyList[vertex] = [];
    }
  }

  // Tilføj edge
  addEdge(vertex1, vertex2) {
    this.adjacencyList[vertex1].push(vertex2);
    this.adjacencyList[vertex2].push(vertex1); // Undirected
  }

  // Fjern edge
  removeEdge(vertex1, vertex2) {
    this.adjacencyList[vertex1] = this.adjacencyList[vertex1]
      .filter(v => v !== vertex2);
    this.adjacencyList[vertex2] = this.adjacencyList[vertex2]
      .filter(v => v !== vertex1);
  }

  // Breadth-First Search
  bfs(start) {
    const queue = [start];
    const visited = new Set([start]);
    const result = [];

    while (queue.length) {
      const vertex = queue.shift();
      result.push(vertex);

      this.adjacencyList[vertex].forEach(neighbor => {
        if (!visited.has(neighbor)) {
          visited.add(neighbor);
          queue.push(neighbor);
        }
      });
    }
    return result;
  }

  // Depth-First Search
  dfs(start, visited = new Set(), result = []) {
    visited.add(start);
    result.push(start);

    this.adjacencyList[start].forEach(neighbor => {
      if (!visited.has(neighbor)) {
        this.dfs(neighbor, visited, result);
      }
    });
    return result;
  }
}