///590. N-ary Tree Postorder Traversal
///Given the root of an n-ary tree, return the postorder traversal of its nodes' values.
public IList <int> Postorder(Node_Childs root)
{
var ans = new List <int>();
PostorderNaryTree(root, ans);
return(ans);
}
///429. N-ary Tree Level Order Traversal
///Given an n-ary tree, return the level order traversal of its nodes' values.
public IList <IList <int> > LevelOrder(Node_Childs root)
{
var ans = new List <IList <int> >();
var nodes = new List <Node_Childs>()
{
root
};
while (nodes.Count > 0)
{
var next = new List <Node_Childs>();
var list = new List <int>();
foreach (var n in nodes)
{
if (n == null)
{
continue;
}
list.Add(n.val);
next.AddRange(n.children);
}
if (list.Count > 0)
{
ans.Add(list);
}
nodes = next;
}
return(ans);
}
///559. Maximum Depth of N-ary Tree
///Given a n-ary tree, find its maximum depth.
public int MaxDepth(Node_Childs root)
{
if (root == null)
{
return(0);
}
return(1 + MaxDepth(root.children));
}
public void PostorderNaryTree(Node_Childs node, IList <int> ans)
{
if (node == null)
{
return;
}
foreach (var child in node.children)
{
if (child != null)
{
PostorderNaryTree(child, ans);
}
}
ans.Add(node.val);
}