I'm having trouble figuring this out using the two pointers together. We must use append/prepend/find to solve this.

import sys # For getting Python Version import random import math

class ListNode: def __init__(self, val = 0, next= None): self.val = val self.next = next

class Slist(): def __init__(self): #NOTHING CAN BE CHANGED HERE self._first = None self._last = None ############################# # WRITE All public functtions BELOW #############################

############################# # All private functions BELOW #############################