Rotate List
Given a list, rotate the list to the right by k places, where k is non-negative.
Example
Given 1->2->3->4->5 and k = 2, return 4->5->1->2->3.
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) {
* val = x;
* next = null;
* }
* }
*/
public class Solution {
/**
* @param head: the List
* @param k: rotate to the right k places
* @return: the list after rotation
*/
public ListNode rotateRight(ListNode head, int k) {
if (head == null || k == 0) {
return head;
}
int len = 0;
ListNode node = head;
while (node != null) {
len++;
node = node.next;
}
k = k % len;
if (k == 0) {
return head;
}
ListNode slow = head, fast = head;
while (k > 0) {
fast = fast.next;
k--;
}
while (fast.next != null) {
slow = slow.next;
fast = fast.next;
}
fast.next = head;
head = slow.next;
slow.next = null;
return head;
}
}
Hope this helps,
Michael
