/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* head;
ListNode* p;
/** @param head The linked list's head.
Note that the head is guaranteed to be not null, so it contains at least one node. */
Solution(ListNode* head) {
this->head = head;
}
/** Returns a random node's value. */
int getRandom() {
int ans = 0, cnt = 0;
p = head;
while(p) {
if(rand() % ++cnt == 0) ans = p->val;
p = p->next;
}
return ans;
}
};
/**
* Your Solution object will be instantiated and called as such:
* Solution* obj = new Solution(head);
* int param_1 = obj->getRandom();
*/
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* head;
ListNode* p;
int len = 0;
/** @param head The linked list's head.
Note that the head is guaranteed to be not null, so it contains at least one node. */
Solution(ListNode* head) {
this->head = head;
}
/** Returns a random node's value. */
int getRandom() {
for(p = this->head, len = 0; p; p = p->next, len++);
int rand_num = rand() % len;
for(p = this->head, len = 0; len != rand_num; p = p->next, len++);
return p->val;
}
};
/**
* Your Solution object will be instantiated and called as such:
* Solution* obj = new Solution(head);
* int param_1 = obj->getRandom();
*/