#include using namespace std; struct node{ int data; node next; node(int val):data(val),next(nullptr){} }; node b(node* head,int value) { node newnode=new node(value); newnode->next=head； return newnode; } //在尾部插入 node* a(node* head,int value){ node* newnode=new node(value); if(!head){ return newnode; } node* current = head; //循环找到最后一个点 while(current->next ){ current=current->next; } current->next=newnode; return head; } int main(){

}