C语言开发中数据结构循环链表的实现技巧

/** 
 * Definition for singly-linked list. 
 * struct ListNode { 
 *   int val; 
 *   ListNode *next; 
 *   ListNode(int x) : val(x), next(NULL) {} 
 * }; 
 */ 
class Solution { 
public: 
  /** 
   * @param head: the list 
   * @param k: rotate to the right k places 
   * @return: the list after rotation 
   */ 
  ListNode *rotateRight(ListNode *head, int k) { 
    // write your code here 
    if(head==NULL) 
      return head; 
    int len = 0; 
    ListNode*temp = head; 
    while(temp) 
    { 
      len++; 
      temp = temp->next; 
    } 
    k%=len; 
    if(k==0) 
      return head; 
    k = len-k; 
    temp = head; 
    while(k>1) 
    { 
      temp = temp->next; 
      k--; 
    } 
    ListNode*newStart = temp->next; 
    temp->next = NULL; 
    temp = newStart; 
    while(temp->next) 
      temp = temp->next; 
    temp->next = head; 
    return newStart; 
  } 
};