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Rotate List

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Question

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

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

Solution

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public ListNode rotateRight(ListNode head, int k) {
    if ( head == null || head.next == null ) return head;
    
    ListNode tmp = head;
    int l = 1;
    while (tmp.next != null) {
        tmp = tmp.next;
        l++;
    }
    
    tmp.next = head;
    for (k = l-k%l; k > 0; k--) 
        tmp = tmp.next;					
    head = tmp.next;
    tmp.next = null;
    return head;
}