LeetCode/com/zerroi/leetcode/Three26/RotateRight.java

package com.zerroi.leetcode.Three26;

import org.w3c.dom.ls.LSException;


public class RotateRight {
    public static void main(String[] args) {
        ListNode head = ListNode.constructLinkedList(new int[]{1, 2, 3, 4, 5});
        SolutionFirst solutionFirst = new SolutionFirst();
        ListNode node = solutionFirst.rotateRight(head, 2);
    }

    public static void print(ListNode head) {
        while (head != null) {
            System.out.println("head = " + head.val);
            head = head.next;
        }
    }
}

class SolutionFirst {
    public ListNode rotateRight(ListNode head, int k) {
//        向右移动k个 可以等价于 将链表后k个节点放到链表头部
        int length = length(head);
        k = k % length;
        if (k == 0) return head;
        ListNode cur = head;
        for (int i = 1; i < length - k; i++) {
            cur = cur.next;
        }
        ListNode temp = cur.next;
        cur.next = null;
        ListNode cur1 = temp;
        while (cur1.next != null) {
            cur1 = cur1.next;
        }
        cur1.next = head;
        return temp;
    }
    
    public int length(ListNode head) {
        int count = 0;
        while (head != null) {
            count++;
            head = head.next;
        }
        return count;
    }
}