33-二叉树遍历-后序遍历mirror

     public void mirrisPre(TreeNode cur) {
         if(cur == null) return;
         TreeNode root = cur; // 保存根节点，因为再后序的遍历中cur引用一直再变。
         TreeNode mostRight = null;
         while(cur != null) {
             mostRight = cur.left; 
             if(mostRight != null) {
                 while(mostRight.right != null && mostRight.right != cur) { // 如果右边不为空，并且右边不指向后继节点的话就找到其前继节点
                    mostRight = mostRight.right;
                 }
                 if(mostRight.right == null) { // 建立线索指针
                     mostRight.right = cur;
                     cur = cur.left;
                     continue;
                 } else { // 删除线索指针
                     mostRight.right = null;
                     printNode(cur.left);
                 }
             } 
             cur = cur.right; // 向右走
         }
         printNode(root.left);  // 打印根节点的最右边链表
    }
    // 打印右边的链表
    public void printNode(TreeNode head) {
        TreeNode tail = reverse(head);
        while(tail != null) {
            System.out.println(tail.val);
            tail = tail.right;
        }
        reverse(tail);
    }
    // 反转链表
    public TreeNode reverse() {
        TreeNode prev = null,curr,next;
        curr = head;
        while(curr != null) {
            next = curr.right;
            curr.right = prev;
            prev = curr;
            curr = next;
        }
        return prev;
    }