Reverse Nodes in k-Group

[fkdl0048]

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     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) {}
 * };
 */
class Solution {
public:
    ListNode* reverseKGroup(ListNode* head, int k) {
        if (!head || k == 1) return head;

        ListNode* dummy = new ListNode(0);
        dummy->next = head;
        ListNode* current = dummy, *next = dummy, *prev = dummy;

        int count = 0;
        while (current->next) {
            current = current->next;
            count++;
        }

        while (count >= k) {
            current = prev->next;
            next = current->next;

            for (int i = 1; i < k; i++) {
                current->next = next->next;
                next->next = prev->next;
                prev->next = next;
                next = current->next;
            }

            prev = current;
            count -= k;
        }

        return dummy->next;
    }
};

• k번 반복으로 묶어서 따로 함수 빼도 될 듯