力扣：61. 旋转链表

 

1、简单做法（勉强算双指针吧） 

/**
 * 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* rotateRight(ListNode* head, int k) {
        if(head==NULL||head->next==NULL||k==0) return head;
        int len=1,cnt;
        ListNode* cru=head;
        while(cru->next!=NULL)
        {
            cru=cru->next;
            ++len;
        }
        cru->next=head;
        cnt=k%len;
        if(cnt==0) cnt==len;
        cru=head;
        head=head->next;
        for(int i=0;inext;
            head=head->next;
        }
        cru->next=NULL;
        return head;
    }
};