[LeetCode] Rotate List

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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.

/** * 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(k==0 || head==NULL || head->next == NULL)            return head;        int len=0;        ListNode *p = head;        while(p){            len++;            p = p->next;        }        while(len<k){           k -= len;        }        ListNode *Pfast = head,*Pslow =head,*h = head;        int i;        for(i=0;Pfast!=NULL && i<k+1;i++){            Pfast = Pfast->next;        }                while(Pfast!=NULL){            Pfast = Pfast->next;            Pslow = Pslow->next;        }//end while;        if(Pslow == head && i< k+1)            return head;        h = Pslow->next;        Pslow->next = NULL;        Pslow = h;        while(Pslow && Pslow->next)            Pslow = Pslow->next;               Pslow->next = head;      return h;            }//end func};