#138

Copy List with Random Pointer

medium· Linked Listruns: 0

A linked list of length n is given such that each node contains an additional random pointer, which could point to any node in the list or null. Construct a deep copy of the list. The deep copy should consist of exactly n brand new nodes whose value and connections mirror the original.

wpm 0acc 100%time 0:000 / 497

class Solution:
    def copyRandomList(self, head: "Node | None") -> "Node | None":
        if not head:
            return None
        old_to_new = {}
        curr = head
        while curr:
            old_to_new[curr] = Node(curr.val)
            curr = curr.next
        curr = head
        while curr:
            old_to_new[curr].next = old_to_new.get(curr.next)
            old_to_new[curr].random = old_to_new.get(curr.random)
            curr = curr.next
        return old_to_new[head]

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