Breadth First Search

• Time : O(n)
• Space : O(n)

class Node {
public:
  string name;
  vector<Node *> children;

  Node(string str) { name = str; }

  vector<string> breadthFirstSearch(vector<string> *array) {
		queue<Node*> q;
		q.push(this);
		while(!q.empty()) {
			auto node = q.front(); q.pop();
			array->push_back(node->name);
			for(auto& child : node->children) {
				q.push(child);
			}
		}
    return *array;
  }

  Node *addChild(string name) {
    Node *child = new Node(name);
    children.push_back(child);
    return this;
  }
};