Rotate List

Rotate List

问题：

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

思路：

　　简单的数学推导问题

我的代码：

public class Solution {

    public ListNode rotateRight(ListNode head, int n) {

        if(head == null || n <= 0) return head;

        int len = 0;

        ListNode dummy = new ListNode(-1);

        dummy.next = head;

        ListNode tail = dummy;

        ListNode cur = head;

        while(cur != null)

        {

            cur = cur.next;

            tail = tail.next;

            len++;

        }

        int gap = len - n%len;

        ListNode last = dummy;

        for(int i = 0; i < gap; i++)

        {

            last = last.next;

        }

        tail.next = dummy.next;

        dummy.next = last.next;

        last.next = null;

        return dummy.next;        

    }

}

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