leetcode并查集，[LeetCode]Rotate List

Given a list, rotate the list to the right by?k?places, where?k?is non-negative.

For example:
Given?1->2->3->4->5->NULL?and?k?=?2,
return?4->5->1->2->3->NULL.

思考：先首尾連成環，head前進(len-k%len)步，拆環。

/*** Definition for singly-linked list.* struct ListNode {*     int val;*     ListNode *next;*     ListNode(int x) : val(x), next(NULL) {}* };*/
class Solution {
public:ListNode *rotateRight(ListNode *head, int k) {if(head==NULL||k==0) return head;ListNode *p=head;int len=1;while(p->next){len++;p=p->next;}p->next=head;k%=len;int step=len-k;while(step--){p=p->next;}head=p->next;p->next=NULL;return head;}
};

leetcode并查集。　　

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