LeetCode 117 Populating Next Right Pointers in Each Node II

Follow up for problem "Populating Next Right Pointers in Each Node".

What if the given tree could be any binary tree? Would your previous solution still work?

Note:

• You may only use constant extra space.

For example,
Given the following binary tree,

         1
       /  \
      2    3
     / \    \
    4   5    7

After calling your function, the tree should look like:

         1 -> NULL
       /  \
      2 -> 3 -> NULL
     / \    \
    4-> 5 -> 7 -> NULL

	public void connect(TreeLinkNode root) {
		if (root == null) return;
		// now find root.next's valid child
		TreeLinkNode n = root.next, nextNodeChild = null;
		while (n != null && nextNodeChild == null) {
			if (n.left != null) {
				nextNodeChild = n.left;
				break;
			}
			if (n.right != null) {
				nextNodeChild = n.right;
				break;
			}
			n = n.next;
		}
		// now nextNodeChild is fetched
		if (root.right != null)
			root.right.next = nextNodeChild;
		if (root.left != null)
			root.left.next = root.right == null ? nextNodeChild : root.right;
		// recursion call
		connect(root.right);
		connect(root.left);
	}

http://www.shuati123.com/blog/2014/05/27/Populating-Next-Right-Pointers-in-Each-Node-II/

方法二  

	public void connect(TreeLinkNode root) {
		while (root != null) {
			TreeLinkNode tempChild = new TreeLinkNode(0);
			TreeLinkNode currentChild = tempChild;
			while (root != null) {
				if (root.left != null) {
					currentChild.next = root.left;
					currentChild = currentChild.next;
				}
				if (root.right != null) {
					currentChild.next = root.right;
					currentChild = currentChild.next;
				}
				root = root.next;
			}
			root = tempChild.next;
		}
	}

https://github.com/int32bit/leetcode/tree/master/algorithms/PopulatingNextRightPointersinEachNodeII