public TreeNodeV2 Connect_BFS(TreeNodeV2 root)
{
var queue = new Queue <TreeNodeV2>();
queue.Enqueue(root);
while (queue.Count != 0)
{
var nodeNumberInCurrLevel = queue.Count;
TreeNodeV2 pre = null;
while (nodeNumberInCurrLevel > 0)
{
var node = queue.Dequeue();
if (node == null)
{
nodeNumberInCurrLevel--;
continue;
}
if (pre != null)
{
pre.next = node;
}
pre = node;
queue.Enqueue(node.left);
queue.Enqueue(node.right);
nodeNumberInCurrLevel--;
}
}
return(root);
}
public TreeNodeV2(int val,
TreeNodeV2 left,
TreeNodeV2 right,
TreeNodeV2 next)
{
this.val = val;
this.left = left;
this.right = right;
this.next = next;
}
public static TreeNodeV2 BuildTreeV2(int?[] input,
int i)
{
if (i >= input.Length || input[i] == null)
{
return(null);
}
var root = new TreeNodeV2(input[i].Value);
root.left = BuildTreeV2(input,
2 * i + 1);
root.right = BuildTreeV2(input,
2 * i + 2);
return(root);
}
public TreeNodeV2 Connect_DFS(TreeNodeV2 root)
{
if (root == null)
{
return(root);
}
var temp = root.next;
TreeNodeV2 nextNodeDownLevel = null;
while (temp != null)
{
if (temp.left != null)
{
nextNodeDownLevel = temp.left;
break;
}
if (temp.right != null)
{
nextNodeDownLevel = temp.right;
break;
}
temp = temp.next;
}
if (root.left != null)
{
root.left.next = root.right ?? nextNodeDownLevel;
}
if (root.right != null)
{
root.right.next = nextNodeDownLevel;
}
Connect_DFS(root.right);
Connect_DFS(root.left);
return(root);
}
public TreeNodeV2 Connect_DFS(TreeNodeV2 root)
{
if (root == null)
{
return(null);
}
if (root.left != null)
{
root.left.next = root.right;
}
if (root.right != null && root.next != null)
{
root.right.next = root.next.left;
}
Connect_DFS(root.left);
Connect_DFS(root.right);
return(root);
}
public static string GetNodeString(TreeNodeV2 root)
{
var queue = new Queue <TreeNodeV2>();
var nodeStr = new List <string>();
var firstNodeFromLeft = new List <TreeNodeV2>();
if (root != null)
{
queue.Enqueue(root);
}
while (queue.Count != 0)
{
var nodeNumberInCurrLevel = queue.Count;
var node = queue.Dequeue();
firstNodeFromLeft.Add(node);
if (node.left != null)
{
queue.Enqueue(node.left);
}
if (node.right != null)
{
queue.Enqueue(node.right);
}
nodeNumberInCurrLevel--;
while (nodeNumberInCurrLevel > 0)
{
node = queue.Dequeue();
if (node.left != null)
{
queue.Enqueue(node.left);
}
if (node.right != null)
{
queue.Enqueue(node.right);
}
nodeNumberInCurrLevel--;
}
}
foreach (var item in firstNodeFromLeft)
{
var node = item;
while (node != null)
{
nodeStr.Add(node.val.ToString());
node = node.next;
}
nodeStr.Add("#");
}
return(string.Join(",",
nodeStr));
}
