复杂链表的复制

请实现 copyRandomList 函数，复制一个复杂链表。在复杂链表中，每个节点除了有一个 next 指针指向下一个节点，还有一个 random 指针指向链表中的任意节点或者 null
参考

"""
# Definition for a Node.
class Node:
    def __init__(self, x: int, next: 'Node' = None, random: 'Node' = None):
        self.val = int(x)
        self.next = next
        self.random = random
"""
class Solution:
    def copyRandomList(self, head: 'Node') -> 'Node':
        if not head:
            return 
        hash = {}
        tem = head
        while tem:
            hash[tem] = Node(tem.val)
            tem = tem.next
        tem = head
        while tem:
            hash[tem].next = hash.get(tem.next)#注意要用get来获取key的vale，这样如果为none，会返回none；用[]会报错
            hash[tem].random = hash.get(tem.random)
            # hash[tem].next = hash[tem.next]
            # hash[tem].random = hash[tem.random]
            tem = tem.next
        return(hash[head])