[leetcode] Copy List with Random Pointer

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public class Solution { public RandomListNode copyRandomList(RandomListNode head) { if(head == null) return null; RandomListNode current = head; while (current != null){ RandomListNode next = current.next; current.next = new RandomListNode(current.label); current.next.next = next; current = next; } current = head; RandomListNode newHead = head.next; while (current != null){ current.next.random = current.random == null?null:current.random.next; RandomListNode currentNext = current.next.next; current = currentNext; } current = head; while (current != null){ RandomListNode temp = current.next; current.next = temp.next; if (temp.next != null){ temp.next = temp.next.next; } current = current.next; } return newHead; } }