#include <stdio.h>
#include <stdlib.h>
#define len sizeof(struct node)
//类似于排序
struct node
{int num;
struct node *next;
};
int main()
{struct node *p,*q,*head,*x,*y;
p=q=malloc(len);
scanf("%d",&p->num);
int i=4;
while(i--)
{if(i==3)head=p;
else q->next=p;...