Populating Next Right Pointers in Each Node

Problem Description: 

Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL.

Initially, all next pointers are set to NULL . We also need to use constant 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

Solution:
Use level order traversal.

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1. public class Solution {  
2.     public void connect(TreeLinkNode root) {  
3.   
4.         while(root != null){  
5.             TreeLinkNode tempChild = new TreeLinkNode(0);  
6.             TreeLinkNode currentChild = tempChild;  
7.             while(root!=null){  
8.                 if(root.left != null) { currentChild.next = root.left; currentChild = currentChild.next;}  
9.                 if(root.right != null) { currentChild.next = root.right; currentChild = currentChild.next;}  
10.                 root = root.next;  
11.             }  
12.             root = tempChild.next;  
13.         }  
14.     }  
15. }  

public class Solution {
    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;
        }
    }
}