1485. Clone Binary Tree With Random Pointer

https://leetcode.com/problems/clone-binary-tree-with-random-pointer/

# Definition for Node.
# class Node:
#     def __init__(self, val=0, left=None, right=None, random=None):
#         self.val = val
#         self.left = left
#         self.right = right
#         self.random = random

class Solution:
    def copyRandomBinaryTree(self, root: 'Node') -> 'NodeCopy':
        self.map = {}
        def dfs(node):
            if not node:
                return None
            if node in self.map:
                return self.map[node]
            copyNode = NodeCopy(node.val)
            self.map[node] = copyNode
            copyNode.left = dfs(node.left)
            copyNode.right = dfs(node.right)
            copyNode.random = dfs(node.random)
            return copyNode
        return dfs(root)