LeetCode 92. 反转链表 II

92. 反转链表 II

class Solution {
public:
    ListNode *reverseBetween(ListNode *head, int left, int right) {
        // 设置 dummyNode 是这一类问题的一般做法
        ListNode *dummyNode = new ListNode(-1);
        dummyNode->next = head;
        ListNode *pre = dummyNode;
        for (int i = 0; i < left - 1; i++) {
            pre = pre->next;
        }
        ListNode *cur = pre->next;
        ListNode *nxt;
        for (int i = 0; i < right - left; i++) {
            nxt = cur->next;
            cur->next = nxt->next;
            nxt->next = pre->next;
            pre->next = nxt;
        }
        return dummyNode->next;
    }
};