List Strong Component

http://wxx5433.github.io/list-strong-component.html#

Given a list of nodes in a doubly linked list. All nodes that are neighbor in the original doubly linked list forms a strong component. Given only the list of nodes, what's the number of strong component?

Example:

The underlying doubly linked list looks like: 1 <-> 2 <-> 4 <-> 7 <-> 9 <-> 11, but this are not given as the input.

The input is a list of nodes: 1, 2, 7, 9, 11. There should be 2 strong component. {1, 2}, {7, 9, 11}

Analysis

The idea is to first add all nodes in the list into a set. Then start from one node, and remove the node and all connected nodes from the set.

  public int getNumStrongComponent(DoublyLinkedListNode[] nodes) {
    int numStrongComponents = 0;
    Set<DoublyLinkedListNode> set = new HashSet<>();
    for (DoublyLinkedListNode node : nodes) {
      set.add(node);
    }
    while (!set.isEmpty()) {
      DoublyLinkedListNode node = set.iterator().next();
      set.remove(node);
      DoublyLinkedListNode cur = node.next;
      while (set.contains(cur)) {
        set.remove(cur);
        cur = cur.next;
      }
      cur = node.prev;
      while (set.contains(cur)) {
        set.remove(cur);
        cur = cur.prev;
      }
      numStrongComponents++;
    }
    return numStrongComponents;
  }

https://www.careercup.com/question?id=18880663