☆打卡算法☆LeetCode 61、旋转链表 算法解析

示例 1：
输入： head = [1,2,3,4,5], k = 2
输出： [4,5,1,2,3]

示例 2：
输入： head = [0,1,2], k = 4
输出： [2,0,1]

public class Solution {
    public ListNode RotateRight(ListNode head, int k) 
    {
        var length = 0;
        var temp = head;
        
        while(temp != null)
        {
            length ++;
            temp = temp.next;
        }

        if(length == 0 || length == 1)
        {
            return head;
        }

        k %= length;

        if(k==0)
        {
            return head;
        }

        var index = length - k;
        var firstNode = head;
        var curLastNode = head;
        while(index>1)
        {
            curLastNode = curLastNode.next;
            index --;
        }
        var newHead = curLastNode.next;
        curLastNode.next = null;

        var nodeTemp = newHead;
        //找到后面的链尾 指向之前链表中第一个元素
        while(nodeTemp.next != null)
        {
            nodeTemp = nodeTemp.next;
        }
        nodeTemp.next = firstNode;
        return newHead;
    }
}