原题链接: https://oj.leetcode.com/problems/rotate-list/

public ListNode rotateRight(ListNode head, int n) {
    if (head == null) {
        return head;
    }

    ListNode cursor = head;

    int length = 0;
    while (cursor != null) {
        cursor = cursor.next;
        length++;
    }

    if (n % length == 0) {
        return head;
    }

    int targetIndex = length - n % length;

    int currentIndex = 0;
    cursor = head;
    ListNode prev = null;

    while (currentIndex < targetIndex) {
        prev = cursor;
        cursor = cursor.next;
        currentIndex++;
    }

    ListNode cursorTail = cursor;
    while (cursorTail.next != null) {
        cursorTail = cursorTail.next;
    }

    prev.next = null;
    cursorTail.next = head;
    head = cursor;

    return head;
}