text: #!/usr/bin/env python3
  # @Date       : 2022/4/9 
  # @Filename   : listnode_notes.py 链表学习记录
  # @Tag        :
  # @Autor      : LI YAO
  # @Difficulty :
  
  from heapq import *
  from typing import List,  Optional
  from collections import defaultdict, deque, Counter
  from itertools import product,combinations,permutations,accumulate
  from random import choice, randrange,randint
  
  class ListNode: 
  	def __init__(self, val=0, next=None):
  		self.val = val
  		self.next = next
  
  first = ListNode(23)
  first.next = ListNode(6)
  first.next.next = ListNode(15)
  
  
  cur = ListNode(9)
  cur.next = first.next.next
  first.next.next = cur
  
  b = first
  while b:
  	if b.next.val == 9:
  		b.next = b.next.next
  		break
  	
  #print(first.val)   first 是不会动的