[Leetcode][python]Copy List with Random Pointer/复制带随机指针的链表

class Solution(object):
    def copyRandomList(self, head):
        """
        :type head: RandomListNode
        :rtype: RandomListNode
        """
        if not head:
            return None
        visited = dict()
        # 复制值
        node = head
        while node:
            visited[node] = RandomListNode(node.label)
            node = node.next

        # 给一个空值
        visited[None] = None

        # 复制关系
        node = head
        while node:
            visited[node].next = visited[node.next]
            visited[node].random = visited[node.random]
            node = node.next
        return visited[head]