ARST- 日常打卡 4

/*// Definition for a Node.class Node {public:    int val;    Node* next;    Node* random;        Node(int _val) {        val = _val;        next = NULL;        random = NULL;    }};*/
class Solution {public:    Node* copyRandomList(Node* head) {        if(head == nullptr) return nullptr;
        Node *p = head, *q, *new_head;        while(p){            q = new Node(p->val);            q->random = p->random;            q->next = p->next;            p->next = q;            p = q->next;        }        p = head->next;        while(p){            if(p->random) p->random = p->random->next;            // p = p->next;            // if(p) p = p->next;            // p = p->next->next;            (p = p->next) && (p=p->next);        }        // 将链表拆开        new_head = head->next;        p = head;        while(p){            q = p->next;            p->next = q->next;            if(p->next) q->next = p->next->next;            p= p->next;            // q=q->next;        }        return new_head;    }};