题解 | #链表中的节点每k个一组翻转#

/**
 * 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) {
        // write code here
        ListNode* dummyNode = new ListNode(-1);
        dummyNode->next = head;
        ListNode* cur = head;
        int cnt = 0;
        while(cur != nullptr){
            cur = cur->next;
            cnt++;
        }
        int times = cnt/k;
        ListNode* prev = dummyNode;
        cur = head;
        while(times--){
            ListNode* curNext = nullptr;
            for(int i = 0; i<k-1; i++){
                curNext = cur->next;
                cur->next = curNext->next;
                curNext->next = prev->next;
                prev->next = curNext;
            }
            prev = cur;
            cur = cur->next;
        }
        return dummyNode->next;

    }
};