4.30 字节后端一面凉凉经+华为软开奇葩一面

两个单向链表从尾部开始相加，返回新的链表。每个节点都是[0-9]的整数。
head------- tail
2-3-4-5
        +
   4-5-6
        =
2-8-0-1
不限语言，数据结构自定义即可，不要求可执行，核心代码逻辑正确，边界考虑。
Node{
int value;
Node * next;
};
List{
Node * header;
}

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        int len1=0;
        int len2=0;
        Node temp1=head1;
        Node temp2=head2;
        while(temp1!=null){
            len1++;
            temp1=temp1.next;
        }
        while(temp2!=null){
            len2++;
            temp2=temp2.next;
        }
        if(len2>len1){
            Node t=head1;
            head1=head2;
            head2=t;
            int lent;
            lent=len1;
            len1=len2;
            len2=lent;
        }
        for(int i=0;i<len1;i++){
            temp1=head1;
            temp2=head2;
            int jiawei=0;
            for(int j=1;j<len1-i;j++){
                temp1=temp1.next;
            }
            if(i<len2){
               for(int j=1;j<len-i;j++){
                    temp2=temp2.next;
                } 
            }
            if(i<len2){
                temp1.val+=temp2.val;
            }
      
            temp1.val+=jinwei;
            if(temp1>10)(
                jinwei=1;
            )else
                jinwei=0;
            temp1%=10;
            
        }
        Node ans;
        if(len1==len2&&head1.val+head2.val>10)(
            ans=new Node(1);
            ans.next.head1;
        )else
           ans=head1; 
    }
}