Populating Next Right Pointers in Each Node II

先遍历右子树

public class Solution {
    public void connect(TreeLinkNode root) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(root == null)
            return;
            
        TreeLinkNode p = root.next;
        while(p != null){
            if(p.left != null){
                p = p.left;
                break;
            } 
            if(p.right != null){
                p = p.right;
                break;
            }
            p = p.next;
        }
        
        if(root.left != null)
        {
            if(root.right != null)
                root.left.next = root.right;
            else
            {
                root.left.next = p;
            }
        }
        
        if(root.right != null)
        {
            root.right.next = p;
        }
        if(root.right!=null)
            connect(root.right);
        if(root.left!=null)
            connect(root.left);
    }
}