Given a list, rotate the list to the right by k places, where k is non-negative.
Example:
Given 1->2->3->4->5->NULL and k = 2, return 4->5->1->2->3->NULL.
Tips:右移结点,过程如下:
k=2,右移两次:
①5->1->2->3->4
②4->5->1->2->3
思路:(1)实例化一个fast指针,使其等于head结点,使fast指针先向后移动k次。
(2)创建一个slow指针,然后两个指针一起向后移动,直到fast.next!=null,停止。
(3)k的值可能大于链表总长度,需要对k取余,k = k%count;
(4)使fast.next等于head,slow的下一个结点作为新的头结点。
package medium; import dataStructure.ListNode; public class L61RotateList { /* * Given a list, rotate the list to the right by k places, where k is * non-negative. * * Example: * * Given 1->2->3->4->5->NULL and k = 2, * * return 4->5->1->2->3->NULL. * */ public ListNode rotateRight(ListNode head, int k) { if(head==null || k<0)return null; ListNode node = new ListNode(0); node.next = head; ListNode fast=head; ListNode newHead=head; int count=0; while(newHead!=null){ count++; newHead=newHead.next; } if(k > count) k = k%count; for(int i=0;i<k;i++){ fast=fast.next; } if(fast==null){ return node.next; }else{ ListNode slow=head; while(fast.next!=null){ slow=slow.next; fast=fast.next; } fast.next=head; ListNode cur=slow.next; node.next=cur; slow.next=null; } return node.next; } public static void main(String[] args) { ListNode head1 = new ListNode(1); ListNode head2 = new ListNode(2); ListNode head3 = new ListNode(3); ListNode head4 = new ListNode(4); ListNode head5 = new ListNode(5); ListNode head6 = null; head1.next = head2; head2.next = head3; head3.next = head4; head4.next = head5; head5.next = head6; L61RotateList l61=new L61RotateList(); int k=2; ListNode node=l61.rotateRight(head1, k); while(node!=null){ System.out.println(node.val); node=node.next; } System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~"); ListNode h1 = new ListNode(1); ListNode h2=new ListNode(2); h1.next=h2; h2.next=null; ListNode node1=l61.rotateRight(h1, 3); while(node1!=null){ System.out.println(node1.val); node1=node1.next; } } }
原文地址:https://www.cnblogs.com/yumiaomiao/p/8448467.html
时间: 2024-10-24 11:51:25