随机链表的复制【链表】【哈希】

Problem: 138. 随机链表的复制

思路 & 解题方法

哈希。

复杂度

时间复杂度:

$O(n)$

空间复杂度:

$O(n)$

Code

"""
# 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: 'Optional[Node]') -> 'Optional[Node]':
        cur = head
        node1 = ans = Node(0, None, None)
        mp = collections.defaultdict(Node)
        while cur:
            node2 = Node(cur.val, None, None)
            node1.next = node2
            node1 = node2
            mp[cur] = node1
            cur = cur.next
        
        cur = head
        ans_cur = ans.next
        while cur:
            if cur.random:
                ans_cur.random = mp[cur.random]
            ans_cur = ans_cur.next
            cur = cur.next
        return ans.next