leetcode

0 class Solution {

1 ListNode *head = nullptr;

2 int size = 0;

3

4 public:

5 Solution(ListNode *head) : head(head) {

6 for (ListNode *p = head; p; p = p->next)

7 size++;

8 }

9

10 int getRandom() {

11 int elem = rand() % size;

12 ListNode *p = head;

13 while (elem--)

14 p = p->next;

15 return p->val;

16 }

17 };