#include using namespace std; /* 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: bool hasCycle(ListNode *head); bool test(ListNode *head, bool answer); };