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class Solution {
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  public ListNode rotateRight(ListNode head, int k) {
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    if (k <= 0 || head == null || head.next == null) {
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      return head;
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    }
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    int length = 1;
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    ListNode first = head;
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    ListNode curr = head;
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    ListNode node = head;
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    while (node.next != null) {
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      length++;
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      node = node.next;
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    }
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    if (k == length) {
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      return head;
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    }
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    int n = length - (k % length);
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    for (int i = 0; i < n - 1; i++) {
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      curr = curr.next;
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    }
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    node.next = head; // 5-->1
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    head = curr.next;
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    curr.next = null;
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    return head;
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  }
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}