Convert hierarchical list to a flat list in java

Question

I have a hierarchical list like below and I want to convert it to a flat list.

I have wrote a method called convertToFlatList

Answer 1

Actually this is the problem of level/recursive order traversal of a tree. Here is detail of the problem and solutions:

https://en.wikipedia.org/wiki/Tree_traversal

By the way, this is traversal (Depth first-Pre order) of your problem:

static class Member {
  List children = new ArrayList<>();
  int id;
  boolean visit = false;
}
public List printList(Member member) {
  Stack stack =  new Stack<>();
  List list =  new ArrayList<>();
  stack.push(member);
  while(!stack.isEmpty()) {
    Member node = stack.pop();
    list.add(node);
    for(Member m: node.children) {
    stack.push(m);
    }
  }
  return list;
}