题解 | #将单链表的每K个节点之间逆序#

import java.io.;
import java.util.;

class Node{
public int value;
public Node next;
public Node(int data){
this.value=data;
}

//String数组转链表   非环
public  static Node tranStringNoLoop(String[] nums){
    Node head=new Node(Integer.parseInt(nums[0]));
    Node cur=head;
    for(int i=1;i<nums.length;i++){
        cur.next=new Node(Integer.parseInt(nums[i]));
        cur=cur.next;
    }
    return head;
}

//打印链表[非环]
public static  void printNodeList(Node head){
    StringBuilder sb=new StringBuilder();
    while (head!=null){
        sb.append(head.value).append(" ");
        head=head.next;
    }
    System.out.println(sb.toString());
}

}

public class Main{
public static Node reverseNodes1(Node head,int K){
if(K<2) {return head;}
Stack<node>stack=new Stack<node>();
Node newHead=head;
Node cur=head;
Node pre=null;
Node next=null;</node></node>

    while(cur!=null){
        next=cur.next;
        stack.push(cur);
        if(stack.size()==K){
            pre=resign1(stack,pre,next);
            newHead = newHead==head?cur:newHead;//第一个K，需要改变头
        }
        cur=next;
    }
    return newHead;
}

public static Node resign1(Stack<Node>stack,Node left,Node right){

    Node cur1=stack.pop();
    if(left!=null){
        left.next=cur1;
    }
    Node next=null;
    while(!stack.isEmpty()){
        next=stack.pop();//控制移动方向

        cur1.next=next;//反转
        cur1=next;//移动
    }
    //连接右边
    cur1.next=right;
    return cur1;
}


public static void main(String[]args)throws IOException{
    BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
    in.readLine();
    String[] nums=in.readLine().split(" ");
    int K=Integer.parseInt(in.readLine());
    Node head=Node.tranStringNoLoop(nums);
    Node head1=reverseNodes1(head,K);
    Node.printNodeList(head1);
}

}