/** * struct ListNode { * int val; * struct ListNode *next; * ListNode(int x) : val(x), next(nullptr) {} * }; */ class Solution { public: /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param head ListNode类 * @return ListNode类 */ ListNode* ReverseList(ListNode* head) { // write code here if(head==nullptr) { return nullptr; } ListNode* p = head; while (p != nullptr) { p = p->next; } ListNode* q, *r; while (head->next != p) { q = head; r = head->next; while (r != p) { int temp = r->val; r->val = q->val; q->val = temp; q = r; r = r->next; } p = q; } return head; } };