class Solution { public: ListNode* reverseBetween(ListNode* head, int m, int n) { auto* dum = new ListNode(0), * pre = dum; dum->next = head; for (int i = 1; i < m; ++i) { // 找到前一个节点 pre = pre->next; } head = pre->next; ListNode* next = head->next, *last = nullptr, *st = head; for (in...