LeetCode之Copy List with Random Pointer

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.

“put the nodes in the original linked list to keep track of the order”

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/** * 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 *p, *q;p = head;while (p){q = p->next;RandomListNode*node=new RandomListNode(p->label);node->next = q;p->next = node;p = q;}p = head;while (p){q = p->next;q->random = (p->random?p->random->next:NULL);p = q->next;}p = head;RandomListNode *copylist = p->next;while (p->next){q = p->next;p->next = q->next;p = q;}return copylist;    }};