5.1.12 Populating Next Right Pointers in Each Node II

public class Solution {
public void connect(TreeLinkNode root) {
if(root == null) return;
if(root.left != null){
root.left.next = root.right == null ? getNext(root) : root.right;
}
if(root.right != null){
root.right.next = getNext(root);
}
connect(root.right);
connect(root.left);
}

private TreeLinkNode getNext(TreeLinkNode n){
TreeLinkNode cur = n;
while(cur.next != null){
cur = cur.next;
if(cur.left != null){
return cur.left;
}
if(cur.right != null){
return cur.right;
}
}
return null;
}
}