Ex_4_1_05.md

title	date	draft	tags	categories
Algorithm4 Java Solution 4.1.05	2020-01-28 06:59:15 +0800	false	JAVA	TECH archives

4.1.05

Problem:

4.1.5 Modify Graph to disallow parallel edges and self-loops.

Solution：

parallel edges: 1-2, 2-1

self-loops: 1-1

code:

Ex_4_1_05.java

  public static void main(String[] args) {
    _Graph g = new _Graph(4);
    g.addEdge(1, 2);
    g.addEdge(1, 3);
    // java.lang.IllegalArgumentException: parallel edges for edge: 2-1
    // g.addEdge(2,1);
    // java.lang.IllegalArgumentException: self loop for vertex: 3
    // g.addEdge(3, 3);
    StdOut.println(g);
//    4 vertices, 2 edges
//    0:
//    1: 3 2
//    2: 1
//    3: 1
  }

    public void addEdge(int v, int w) {
      checkSelfLoop(v, w);
      checkParallelEdges(v, w);
      adj[v].add(w);
      adj[w].add(v);
      E++;
    }

Reference：