每日一练 bm3 bm2

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
    public ListNode reverseKGroup (ListNode head, int k) {
        // write code here
        int count=0;
        ListNode cur=head;
        while(cur!=null&&count!=k)
        {cur=cur.next;
         count++;
        }
        cur=reverseKGroup(cur,k);
        
        while(count!=0)
        {
            count--;
            ListNode tmp=head.next;
            head.next=cur;
            cur=head;
            head=tmp;
        }return head;
    }
}
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在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
    public ListNode reverseKGroup (ListNode head, int k) {
        // write code here
        int count=0;
        ListNode cur=head;
        while(cur!=null&&count!=k)
        {cur=cur.next;
         count++;
        }
        cur=reverseKGroup(cur,k);
     if(count==k){
        while(count!=0)
        {
            count--;
            ListNode tmp=head.next;
            head.next=cur;
            cur=head;
            head=tmp;
        }head=cur;
         }return head;
    }
}
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在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
    public ListNode reverseKGroup (ListNode head, int k) {
        // write code here
        int count=0;
        ListNode cur=head;
        while(cur!=null&&count!=k)
        {cur=cur.next;
         count++;
        }
        cur=reverseKGroup(cur,k);
     if(count==k){
        while(count!=0)
        {
            count--;
            ListNode tmp=head.next;
            head.next=cur;
            cur=head;
            head=tmp;
        }head=cur;
         }return head;
    }
}
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该改 首字母bingying拼音无显示
该字上面

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
    public ListNode reverseKGroup (ListNode head, int k) {
        // write code here
        int count=0;
        ListNode cur=head;
        while(cur!=null&&count!=k)
        {cur=cur.next;
         count++;
        }
         if(count==k){ cur=reverseKGroup(cur,k);
   
        while(count!=0)
        {
            count--;
            ListNode tmp=head.next;
            head.next=cur;
            cur=head;
            head=tmp;
        }head=cur;
         }return head;
    }
}
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bm2
不会了又 直接看答案先

import java.util.*;
 
/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */
 
public class Solution {
    /**
     *
     * @param head ListNode类
     * @param m int整型
     * @param n int整型
     * @return ListNode类
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        // write code here
   
        ListNode newHead=new ListNode(-1);
        newHead.next=head;
         
        ListNode prev=newHead;
        for(int i=0;i<m-1;i++)
        {
            prev=prev.next;
        }
        ListNode rightNode=prev;
        for(int i=0;i<n-m+1;i++)
        {
            rightNode=rightNode.next;
        }
         
        ListNode leftNode=prev.next;
        ListNode cur=rightNode.next;
         
        prev.next=null;
       rightNode.next=null;
         
        reverseList(leftNode);
         
        prev.next=rightNode;
        leftNode.next=cur;
        return newHead.next;}
 
 private void  reverseList(ListNode head)
 {
     
     ListNode prev=head;
     ListNode cur=null;
     while(prev!=null)
     {ListNode prev_next=prev.next;
     prev.next=cur;
      cur=prev;
     prev=prev_next;    
     }
 }
      
 }
 
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在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        // write code here
     ListNode NewHead=new ListNode(-1);
      ListNode prev=head;  
        for(int i=0;i<m-1;i++)
        {
            prev=prev.next;
        }
        ListNode rightNode=prev;
        for(int i=0;i<n-m+1;i++)
        {
            rightNode=rightNode.next
        }
        ListNode leftNode=prev.next;
        ListNode cur=rightNode.next;
        reverseList(leftNode);
        prev.next=rightNode;
        leftNode.next=cur; 
        return NewHead.next;
            
    }
    public ListNode reverseList(ListNode head){
        ListNode cur=null;
        ListNode prev=head;
        while(prev!=null)
        {
            ListNode prev_next=prev.next;
             prev.next=cur;
        cur=prev;
            prev=prev_next;
        }
        return cur;
    }
}
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yinggai应该是逆置函数返回为荣wrong
区别是啥？void 和listnode
https://www.baidu.com/baidu?tn=monline_3_dg&ie=utf-8&wd=void+%E5%92%8C+listnode+%E6%9C%89%E5%95%A5%E5%8C%BA%E5%88%AB

https://www.baidu.com/s?ie=utf-8&f=3&rsv_bp=1&tn=monline_3_dg&wd=public%20void%E6%98%AF%E4%BB%80%E4%B9%88%E6%84%8F%E6%80%9D&oq=void%2520%25E5%2592%258C%2520listnode%2520%25E6%259C%2589%25E5%2595%25A5%25E5%258C%25BA%25E5%2588%25AB&rsv_pq=87cab69a0000423d&rsv_t=32abKsP7ub4JoI48IsmFQWHJxaRUu4p6tLOqQjSXJXBcd%2B3t%2Ba3lGTcnO%2BZ9k14%2FEAJU&rqlang=cn&rsv_enter=1&rsv_dl=ts_1&rsv_sug3=14&rsv_sug1=13&rsv_sug7=101&rsv_sug2=1&rsv_btype=t&prefixsug=public%2520void&rsp=1&inputT=7534&rsv_sug4=18081
java里public是类的访问修饰符，void 是表示空类型，没有返回数据。
https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&tn=monline_3_dg&wd=public%20void%20public%20listnode&oq=public%2520void%25E6%2598%25AF%25E4%25BB%2580%25E4%25B9%2588%25E6%2584%258F%25E6%2580%259D&rsv_pq=e6e74dde000107b8&rsv_t=2b6c1PBdGIcDYzEKyWUSw5bfCvROJaS6GnOoRzDZuePGUbyZyGm0qBZO2MhI48TBnYcf&rqlang=cn&rsv_enter=1&rsv_dl=tb&rsv_btype=t&inputT=8892&rsv_sug3=38&rsv_sug1=26&rsv_sug7=100&rsv_sug2=0&prefixsug=public%2520void%2520public%2520listnode&rsp=0&rsv_sug4=9804
https://www.baidu.com/s?wd=public%20listnode&pn=10&oq=public%20listnode&tn=monline_3_dg&ie=utf-8&rsv_pq=9ccbbb4600018810&rsv_t=1d027Ft0qcVrPKQjFCxDwCB4RQvqKatXMOkpedM6ppW2mFfcn5tIHIVi75vfixqNTHaX
为什么链表的反转不需要返回值
返回值是社么什么
https://m.imooc.com/wenda/detail/337550
。当然，如果这个方法在执行完之后不需要返回任何数据，返回值类型必须写void关键字，不能空着不写。
https://blog.csdn.net/weixin_33104731/article/details/114022985
为什么要定义一个void的返回类型
https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&tn=monline_3_dg&wd=%20%E4%B8%BA%E4%BB%80%E4%B9%88%E8%A6%81%E5%AE%9A%E4%B9%89%E4%B8%80%E4%B8%AAvoid%E7%9A%84%E8%BF%94%E5%9B%9E%E7%B1%BB%E5%9E%8B&oq=%25E8%25BF%2594%25E5%259B%259E%25E5%2580%25BC%25E6%2598%25AF%25E4%25BB%2580%25E4%25B9%2588java&rsv_pq=a95851a000001ef1&rsv_t=c9f4sE1ecLCje%2Bd68pG3WqPI5pN0vYbvECznaiUXSKOzmvjtoSes%2BeSKsq0T9wCpkC8J&rqlang=cn&rsv_enter=0&rsv_dl=tb&rsv_btype=t&rsv_sug3=127&rsv_sug1=60&rsv_sug7=100&prefixsug=%2520%25E4%25B8%25BA%25E4%25BB%2580%25E4%25B9%2588%25E8%25A6%2581%25E5%25AE%259A%25E4%25B9%2589%25E4%25B8%2580%25E4%25B8%25AAvoid%25E7%259A%2584%25E8%25BF%2594%25E5%259B%259E%25E7%25B1%25BB%25E5%259E%258B&rsp=0&rsv_sug4=2244
java
https://blog.csdn.net/qq_56751933/article/details/120737666
https://www.likecs.com/show-203713019.html
https://www.likecs.com/show-203713019.html
java 为什么要定义一个void 的返回类型 链表
private是否只能指定void
https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&tn=monline_3_dg&wd=private%E6%98%AF%E5%90%A6%E5%8F%AA%E8%83%BDvoid&oq=%25E4%25B8%25BA%25E4%25BB%2580%25E4%25B9%2588%25E8%25A6%2581%25E5%25AE%259A%25E4%25B9%2589%25E4%25B8%2580%25E4%25B8%25AAvoid%25E7%259A%2584%25E8%25BF%2594%25E5%259B%259E%25E7%25B1%25BB%25E5%259E%258Bjava%25E9%2593%25BE%25E8%25A1%25A8&rsv_pq=ae007a8400005fb4&rsv_t=dd567YNhk7%2FiPaKWnKdJURhIKWfKNn5MNX0en%2Bzom%2FwfAwnLoVrooqSHy%2BEsKB7pHqdg&rqlang=cn&rsv_enter=0&rsv_dl=tb&rsv_btype=t&inputT=9957&rsv_sug3=175&rsv_sug1=80&rsv_sug7=100&rsv_sug2=0&rsv_sug4=11084
https://blog.csdn.net/weixin_45105160/article/details/119927792
问了
类里面调用私有方法 需要获取私有方法返回值吗
https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&tn=monline_3_dg&wd=%20%E7%B1%BB%E9%87%8C%E9%9D%A2%E8%B0%83%E7%94%A8%E7%A7%81%E6%9C%89%E6%96%B9%E6%B3%95%20%E9%9C%80%E8%A6%81%E8%8E%B7%E5%8F%96%E7%A7%81%E6%9C%89%E6%96%B9%E6%B3%95%E8%BF%94%E5%9B%9E%E5%80%BC%E5%90%97&oq=private%25E6%2598%25AF%25E5%2590%25A6%25E5%258F%25AA%25E8%2583%25BDvoid&rsv_pq=8456b57800012f29&rsv_t=6d23lh%2F8psvbOxgGZ7E%2BSe9N0iEoXvdE4v7sNpPdwcon6Jt%2F4rvU9MxVyv7Ufs1ykxey&rqlang=cn&rsv_enter=0&rsv_dl=tb&rsv_btype=t&rsv_sug3=178&rsv_sug1=83&rsv_sug7=100&prefixsug=%2520%25E7%25B1%25BB%25E9%2587%258C%25E9%259D%25A2%25E8%25B0%2583%25E7%2594%25A8%25E7%25A7%2581%25E6%259C%2589%25E6%2596%25B9%25E6%25B3%2595%2520%25E9%259C%2580%25E8%25A6%2581%25E8%258E%25B7%25E5%258F%2596%25E7%25A7%2581%25E6%259C%2589%25E6%2596%25B9%25E6%25B3%2595%25E8%25BF%2594%25E5%259B%259E%25E5%2580%25BC%25E5%2590%2597&rsp=0&rsv_sug4=3718
在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        // write code here
     ListNode NewHead=new ListNode(-1);
      ListNode prev=head;  
        for(int i=0;i<m-1;i++)
        {
            prev=prev.next;
        }
        ListNode rightNode=prev;
        for(int i=0;i<n-m+1;i++)
        {
            rightNode=rightNode.next;
        }
        ListNode leftNode=prev.next;
        ListNode cur=rightNode.next;
        prev.next=null;
        rightNode.next=null;
        reverseList(leftNode);
        prev.next=rightNode;
        leftNode.next=cur; 
        return NewHead.next;
            
    }
    public void reverseList(ListNode head){
        ListNode cur=null;
        ListNode prev=head;
        while(prev!=null)
        {
            ListNode prev_next=prev.next;
             prev.next=cur;
        cur=prev;
            prev=prev_next;
        }
       
    }
}
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在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        // write code here
     ListNode NewHead=new ListNode(-1);
        NewHead.next=head;
      ListNode prev=head;  
        for(int i=0;i<m-1;i++)
        {
            prev=prev.next;
        }
        ListNode rightNode=prev;
        for(int i=0;i<n-m+1;i++)
        {
            rightNode=rightNode.next;
        }
        ListNode leftNode=prev.next;
        ListNode cur=rightNode.next;
        prev.next=null;
        rightNode.next=null;
        reverseList(leftNode);
        prev.next=rightNode;
        leftNode.next=cur; 
        return NewHead.next;
            
    }
    public void reverseList(ListNode head){
        ListNode cur=null;
        ListNode prev=head;
        while(prev!=null)
        {
            ListNode prev_next=prev.next;
             prev.next=cur;
        cur=prev;
            prev=prev_next;
        }
       
    }
}
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在这里插入代码片

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        // write code here
     ListNode NewHead=new ListNode(-1);
        NewHead.next=head;
      ListNode prev=NewHead;  
        for(int i=0;i<m-1;i++)
        {
            prev=prev.next;
        }
        ListNode rightNode=prev;
        for(int i=0;i<n-m+1;i++)
        {
            rightNode=rightNode.next;
        }
        ListNode leftNode=prev.next;
        ListNode cur=rightNode.next;
        prev.next=null;
        rightNode.next=null;
        reverseList(leftNode);
        prev.next=rightNode;
        leftNode.next=cur; 
        return NewHead.next;
            
    }
    public void reverseList(ListNode head){
        ListNode cur=null;
        ListNode prev=head;
        while(prev!=null)
        {
            ListNode prev_next=prev.next;
             prev.next=cur;
        cur=prev;
            prev=prev_next;
        }
       
    }
}
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