关于1002. A+B for Polynomials (25)的某些问题

Question

/*在使用单链表测试时有部分数据出错，不知道哪里有问题，烦请看一下代码，或者说一下应该测试哪几类特殊数据？
 再者使用顺序表方法（代码未贴，且已通过测试）进行时，用时反而少，请问单链表适用于哪里，会显示出它的优点？*/
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
typedef struct{
    int expn;//指数
    double coef;//系数
}term,ElemType;
typedef struct LNode{
    ElemType data;
    struct LNode *next;
}LNode,*LinkList;
typedef LinkList polynomial;
void CreatPolyn(polynomial &p,int m);
void PrintPolyn(polynomial p);
void AddPolyn(polynomial &pa,polynomial &pb);//pa=pa+pb,并销毁一元多项式pb
int main(){
    polynomial pa,pb;
    int ma,mb;
    scanf("%d",&ma);//输入多项式的个数
    CreatPolyn(pa,ma);
    scanf("%d",&mb);
    CreatPolyn(pb,mb);
    AddPolyn(pa,pb);由于题目要求输入数据是按顺序排列的，就没有进行排序处理
    PrintPolyn(pa);
    return 0;
}
void CreatPolyn(polynomial &p,int m){
    polynomial q,rear;
    rear=(polynomial)malloc(sizeof(LNode));
    p=rear;
    rear->data.coef=rear->data.expn=0;
    rear->next=NULL;
    for(int i=0;i<m;i++){
        q=(polynomial)malloc(sizeof(LNode));
        scanf("%d %lf",&(q->data.expn),&(q->data.coef));
        rear->next=q;
        rear=q;
        rear->next=NULL;
    }
}
void PrintPolyn(polynomial p){
    polynomial q;
    q=p->next;
    int count=0;
    while(q){
        count++;
        q=q->next;
    }
    printf("%d",count);
    q=p->next;
    while(q){
        printf(" %d %.2lf",q->data.expn,q->data.coef);
        q=q->next;
    }
    printf("\n");
    free(q);
    q=NULL;
}
void AddPolyn(polynomial &pa,polynomial &pb){
     polynomial qa,qb,rear;
     rear=pa;
     qa=pa->next;qb=pb->next;
     while(qa&&qb){
        if(qa->data.expn>qb->data.expn){
            rear->next=qa;
            rear=qa;
            qa=qa->next;
        }
        else if(qa->data.expn<qb->data.expn){
            rear->next=qb;
            rear=qb;
            qb=qb->next;
        }
        else{
            if((qa->data.coef+qb->data.coef)){
                qa->data.coef+=qb->data.coef;
                rear->next=qa;
                rear=qa;
            }
            qa=qa->next;
            qb=qb->next;
        }
     }
     while(qa){
        rear->next=qa;
        rear=qa;
        qa=qa->next;
     }
     while(qb){
        rear->next=qb;
        rear=qb;
        qb=qb->next;
     }
     free(pb);
     pb=NULL;
}