description:
Given a linked list, rotate the list to the right by k places, where k is non-negative.
Note:
Example:
Example 1:
Input: 1->2->3->4->5->NULL, k = 2
Output: 4->5->1->2->3->NULL
Explanation:
rotate 1 steps to the right: 5->1->2->3->4->NULL
rotate 2 steps to the right: 4->5->1->2->3->NULL
Example 2:
Input: 0->1->2->NULL, k = 4
Output: 2->0->1->NULL
Explanation:
rotate 1 steps to the right: 2->0->1->NULL
rotate 2 steps to the right: 1->2->0->NULL
rotate 3 steps to the right: 0->1->2->NULL
rotate 4 steps to the right: 2->0->1->NULL
answer:
/**
* 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) return NULL;
ListNode* cur = head;
int n = 1;
while(cur->next){
n++;
cur = cur->next;
}
cur ->next = head;
int m = n - k%n;
for (int i = 0; i < m; ++i) {
cur = cur->next;
}
ListNode *newhead = cur -> next;
cur->next = NULL;
return newhead;
}
};