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Copy List with Random Pointer.py
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Copy List with Random Pointer.py
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# Github: Shantanugupta1118
# DAY 43 of DAY 100
# 138. Copy List with Random Pointer - LeetCode/LinkedList
# https://leetcode.com/problems/copy-list-with-random-pointer/
"""
# 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 head is None:
return None
ptr = head
while ptr:
new_node = Node(ptr.val, ptr.next, None)
ptr.next = new_node
ptr = new_node.next
ptr = head
while ptr:
ptr.next.random = ptr.random.next if ptr.random is not None else None
ptr = ptr.next.next
old = head
new = head.next
new_head = new
while old:
old.next = old.next.next
new.next = new.next.next if new.next is not None else None
old = old.next
new = new.next
return new_head