Graph Example

class Graph {
  private vertices: (string | number)[] = [];
  private adjList: Dictionary<string | number, (string | number)[]> =
    new Dictionary();

  constructor(private isDirected = false) {}

  public addVertex(v: string | number) {
    if (!this.vertices.includes(v)) {
      this.vertices.push(v);
      this.adjList.set(v, []); // initialize adjacency list with array as well;
    }
  }

  public addEdge(a: string | number, b: string | number) {
    if (!this.adjList.get(a)) {
      this.addVertex(a);
    }
    if (!this.adjList.get(b)) {
      this.addVertex(b);
    }

    this.adjList.get(a).push(b);

    if (!this.isDirected) {
      this.adjList.get(b).push(a);
    }
    // adjList.get(w).push(v); //commented to run the improved DFS with topological sorting
  }

  public getVertices() {
    return this.vertices;
  }

  public getAdjList() {
    return this.adjList;
  }

  public toString() {
    let s = "";
    for (let i = 0; i < this.vertices.length; i++) {
      s += this.vertices[i] + " -> ";
      const neighbors = this.adjList.get(this.vertices[i]);
      for (let j = 0; j < neighbors.length; j++) {
        s += neighbors[j] + " ";
      }
      s += "\n";
    }
    return s;
  }
}