/** * struct ListNode { * int val; * struct ListNode *next; * }; */ class Solution { public: /** * * @param head ListNode类 * @param k int整型 * @return ListNode类 */ ListNode* reverseKGroup(ListNode* head, int k) { int len = 0; ListNode* p = head; while(p!=nullptr){ p = p->next; len++; } if(len <...