/** * 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 || root.left == null) return; connectNode(root.left,root.right); } public void connectNode(TreeLinkNode p1,TreeLinkNode p2){ p1.next = p2; if(p1.left!=null){ connectNode(p1.left,p1.right); connectNode(p1.right,p2.left); connectNode(p2.left,p2.right); } } }