public static IList <int> BoundaryOfBinaryTree(LeetCode545TreeNode root)
{
var res = new List <int>();
if (root == null)
{
return(res);
}
if (!root.IsLeaf())
{
res.Add(root.val);
}
var temp = root.left;
while (temp != null)
{
if (!temp.IsLeaf())
{
res.Add(temp.val);
}
if (temp.left != null)
{
temp = temp.left;
}
else
{
temp = temp.right;
}
}
AddLeaves(res, root);
var stack = new Stack <int>();
temp = root.right;
while (temp != null)
{
if (!temp.IsLeaf())
{
stack.Push(temp.val);
}
if (temp.right != null)
{
temp = temp.right;
}
else
{
temp = temp.left;
}
}
while (stack.Count != 0)
{
res.Add(stack.Pop());
}
return(res);
}
public static void AddLeaves(IList <int> res, LeetCode545TreeNode root)
{
if (root.IsLeaf())
{
res.Add(root.val);
}
else
{
if (root.left != null)
{
AddLeaves(res, root.left);
}
if (root.right != null)
{
AddLeaves(res, root.right);
}
}
}
public LeetCode545TreeNode(int val = 0, LeetCode545TreeNode left = null, LeetCode545TreeNode right = null)
{
this.val = val;
this.left = left;
this.right = right;
}