import java.util.*; public class Solution { public void connect(TreeLinkNode root) { if(root==null) return ; Queue<TreeLinkNode> q = new LinkedList<>(); q.offer(root); while(!q.isEmpty()){ int size = q.size(); int t = 0; while(t < size){ TreeLinkNode temp = q.remove(); if(temp.left!=null) q.offer(temp.left); if(temp.right!=null) q.offer(temp.right); if(t == size - 1) temp.next = null; else temp.next = q.peek(); t++; } } } }