[LeetCode] Populating Next Right Pointers in Each Node

Thought:
Recursion.

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

Thought: using a Level Order Traversal will be more clear and common.

Code:
public void connect(TreeLinkNode root) {
        if (root == null) return;
        Queue<TreeLinkNode> q1 = new LinkedList<TreeLinkNode>();
        Queue<Integer> q2 = new LinkedList<Integer>();
        q1.offer(root);
        q2.offer(1);
        while (!q1.isEmpty()) {
            TreeLinkNode current = q1.poll();
            int level = q2.poll();
            if (q2.peek() != null && q2.peek() == level) {
                current.next = q1.peek();
            }
            //do something with current
            if (current.left != null) {
                q1.offer(current.left);
                q2.offer(level + 1);
            }
            if (current.right != null) {
                q1.offer(current.right);
                q2.offer(level + 1);
            }
        }

    }