# Leetcode 117 Populating Next Right Pointers in Each Node II.

**Problem 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
```

A very interesting problem, similar to Populating Next Right Pointers in Each Node.

But as the tree have possibility that is not a full tree, so we have to consider the problem from the right side. Use a point to determine the right one we should connect to, then do from the left.

```
/**
* Definition for binary tree with next pointer.
* public class TreeLinkNode {
* int val;
* TreeLinkNode left, right, next;
* TreeLinkNode(int x) { val = x; }
* }
*/
public class Solution {
public void connect(TreeLinkNode root) {
if(root==null){
return;
}
TreeLinkNode p=root.next;
while(p!=null){
if(p.left!=null){
p=p.left;
break;
}
if(p.right!=null){
p=p.right;
break;
}
p=p.next;
}
if(root.right!=null){
root.right.next = p;
}
if(root.left!=null){
if(root.right!=null){
root.left.next=root.right;
}else{
root.left.next=p;
}
//root.left.right.next=root.right.left;
}
connect(root.right);
connect(root.left);
}
}
```