题目描述

blablabla

样例

/**
 * Definition for singly-linked list with a random pointer.
 * struct ListNode {
 *     int val;
 *     ListNode *next, *random;
 *     ListNode(int x) : val(x), next(NULL), random(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *copyRandomList(ListNode *head) {
        if (!head) return head;
        auto p = head;

        while(p) {
            auto tmp = new ListNode(p->val);
            auto t = p->next;
            p->next = tmp;
            tmp->next = t;
            p = t;
        }
        p = head;
        while(p){
            if(p->random)
            p->next->random = p->random->next;
            p = p->next->next;

        }
        p = head;
        auto dummy = new ListNode(-1);
        auto cur = dummy;
        while(p) {

        cur->next = p->next;
        cur = cur->next;
        p = cur->next;

        }
        return dummy->next;
    }
};