public IList <int> NaryPreorderIter(NaryNode root)
{
var results = new List <int>();
if (root == null)
{
return(results);
}
Stack <NaryNode> stack = new Stack <NaryNode>();
stack.Push(root);
while (stack.Count > 0)
{
var node = stack.Pop();
results.Add(node.val);
if (node.children == null)
{
continue;
}
for (int i = node.children.Count - 1; i >= 0; i--)
{
stack.Push(node.children[i]);
}
}
return(results);
}
//https://leetcode.com/problems/maximum-depth-of-n-ary-tree/
public int MaxDepthNary(NaryNode root)
{
if (root == null)
{
return(0);
}
int level = 0;
Queue <NaryNode> q = new Queue <NaryNode>();
q.Enqueue(root);
while (q.Count > 0)
{
var count = q.Count;
level += 1;
for (int i = 0; i < count; i++)
{
var node = q.Dequeue();
for (int j = 0; j < node.children.Count; j++)
{
q.Enqueue(node.children[j]);
}
}
}
return(level);
}
//https://leetcode.com/problems/n-ary-tree-postorder-traversal/
public IList <int> NaryPostorder(NaryNode root)
{
if (root == null)
{
throw new ArgumentNullException(nameof(root));
}
IList <int> results = new List <int>();
Stack <NaryNode> leftStack = new Stack <NaryNode>();
Stack <NaryNode> rightStack = new Stack <NaryNode>();
leftStack.Push(root);
while (leftStack.Count > 0)
{
var current = leftStack.Pop();
for (int i = 0; i < current.children.Count; i++)
{
leftStack.Push(current.children[i]);
}
rightStack.Push(current);
}
while (rightStack.Count > 0)
{
results.Add(rightStack.Pop().val);
}
return(results);
}
public IList <int> NaryPreorder(NaryNode root)
{
var results = new List <int>();
NaryPreorderWorker(root, results);
return(results);
}
public IList <int> NaryPostorderIter(NaryNode root)
{
var results = new List <int>();
if (root == null)
{
return(results);
}
Stack <NaryNode> stackLeft = new Stack <NaryNode>();
Stack <int> stackRight = new Stack <int>();
stackLeft.Push(root);
while (stackLeft.Count > 0)
{
var current = stackLeft.Pop();
foreach (var item in current.children)
{
stackLeft.Push(item);
}
stackRight.Push(current.val);
}
while (stackRight.Count > 0)
{
results.Add(stackRight.Pop());
}
return(results);
}
public IList <int> NaryPreorder(NaryNode root)
{
IList <int> results = new List <int>();
if (root != null)
{
NaryPreorderWorker(root, results);
}
return(results);
}
void MaxDepthNaryWorker(NaryNode root)
{
if (root == null)
{
return;
}
MaxDepthNaryLevel += 1;
for (int i = 0; i < root.children.Count; i++)
{
MaxDepthNary(root.children[i]);
}
}
void NaryPreorderWorker(NaryNode node, IList <int> results)
{
if (node == null)
{
return;
}
results.Add(node.val);
for (int i = 0; i < node.children.Count; i++)
{
NaryPreorderWorker(node.children[i], results);
}
return;
}
void NaryPreorderWorker(NaryNode node, IList <int> results)
{
if (node == null)
{
return;
}
results.Add(node.val);
foreach (var item in node.children)
{
NaryPreorderWorker(item, results);
}
return;
}
public int MaxDepthNary2(NaryNode root)
{
if (root == null)
{
return(0);
}
int max = 0;
for (int i = 0; i < root.children.Count; i++)
{
max = Math.Max(max, MaxDepthNary2(root.children[i]));
}
return(max + 1);
}
//https://leetcode.com/problems/n-ary-tree-preorder-traversal/
public IList <int> NaryPreorderIter(NaryNode root)
{
IList <int> results = new List <int>();
if (root == null)
{
return(results);
}
Stack <NaryNode> stack = new Stack <NaryNode>();
stack.Push(root);
while (stack.Count > 0)
{
var current = stack.Pop();
results.Add(current.val);
for (int i = current.children.Count - 1; i >= 0; i--)
{
stack.Push(current.children[i]);
}
}
return(results);
}
public int MaxDepthNaryIter(NaryNode root)
{
var level = 0;
if (root != null)
{
Queue <NaryNode> q = new Queue <NaryNode>();
q.Enqueue(root);
while (q.Count > 0)
{
level += 1;
var count = q.Count;
for (int i = 0; i < count; i++)
{
var node = q.Dequeue();
foreach (NaryNode item in node.children)
{
q.Enqueue(item);
}
}
}
}
return(level);
}
public int MaxDepthNary(NaryNode root)
{
MaxDepthNaryWorker(root);
return(MaxDepthNaryLevel);
}