public TreeNode2(int _val, TreeNode2 _left, TreeNode2 _right, TreeNode2 _next)
{
val = _val;
left = _left;
right = _right;
next = _next;
}
/// <summary>
/// 给定一棵二叉树，返回它的自左向右同级连接
/// </summary>
/// <param name="root"></param>
/// <returns></returns>
public TreeNode2 Connect2(TreeNode2 root)
{
Dictionary <int, TreeNode2> layersDict = new Dictionary <int, TreeNode2>();
DoRecursionByConnect2(root, 1, layersDict);
return(root);
}
/// <summary>
/// 给定一棵perfect tree，要求自左向右连接它的同层
/// </summary>
/// <param name="root"></param>
/// <returns></returns>
public TreeNode2 Connect(TreeNode2 root)
{
TreeNode2 doRoot = root;
Queue <TreeNode2> doQueue = new Queue <TreeNode2>();
if (root != null)
{
doQueue.Enqueue(root);
int loopNum = 1;
while (doQueue.Count > 0)
{
TreeNode2 tmp1 = doQueue.Dequeue();
for (int i = 1; i < loopNum; i++)
{
TreeNode2 tmp2 = doQueue.Dequeue();
tmp1.next = tmp2;
if (tmp1.left != null)//due to the defination
{
doQueue.Enqueue(tmp1.left);
doQueue.Enqueue(tmp1.right);
}
tmp1 = tmp2;
}
if (tmp1.left != null)
{
doQueue.Enqueue(tmp1.left);
doQueue.Enqueue(tmp1.right);
}
loopNum = loopNum << 1;
}
}
return(root);
}
private void DoRecursionByConnect2(TreeNode2 root, int depth, Dictionary <int, TreeNode2> layersDict)
{
if (root == null)
{
return;
}
if (!layersDict.ContainsKey(depth))
{
layersDict.Add(depth, root);
}
else
{
layersDict[depth].next = root;
layersDict[depth] = root;
}
DoRecursionByConnect2(root.left, depth + 1, layersDict);
DoRecursionByConnect2(root.right, depth + 1, layersDict);
}
