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) {}

ListNode* removeNthFromEnd(ListNode* head, int n);

static void test()

{

ListNode node5{5, nullptr};

ListNode node4{4, &node5};

ListNode node3{3, &node4};

ListNode node2{2, &node3};

ListNode node1{1, &node2};

Solution19 s;

auto res = s.removeNthFromEnd(&node1, 2);

while (res) {

printf("%d\n", res->val);

res = res->next;

}

}