A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.
Return a deep copy of the list.
/** * Definition for singly-linked list with a random pointer. * struct RandomListNode { * int label; * RandomListNode *next, *random; * RandomListNode(int x) : label(x), next(NULL), random(NULL) {} * }; */ class Solution { public: RandomListNode *copyRandomList(RandomListNode *head) { if (head == NULL) return NULL; RandomListNode* cur = head; while (cur != NULL) { RandomListNode* x = new RandomListNode(cur->label); x->next = cur->next; cur->next = x; cur = x->next; } cur = head; while (cur != NULL) { if (cur->random != NULL) cur->next->random = cur->random->next; cur = cur->next->next; } RandomListNode myhead(99); cur = head; RandomListNode* newcur = &myhead; while (cur != NULL) { newcur->next = cur->next; newcur = newcur->next; cur->next = cur->next->next; cur = cur->next; } newcur->next = NULL; return myhead.next; } };