问题是用链表实现多项式的加法和乘法

#include <stdio.h>
#include <stdlib.h>
typedef struct PolyNode* PolyNomial;
struct PolyNode{
    int coef;//conficient 系数
    int expon;//exponenmial 指数
    PolyNomial link; 
};
void Attach(int c,int e,PolyNomial *pRear){
//链接到数组里
    PolyNomial P;
    P=(PolyNomial)malloc(sizeof(struct PolyNode));
    P->coef=c;
    P->expon=e;
    P->link=NULL;
    (*pRear)->link=P;
    *pRear=P;
}
PolyNomial ReadPoly( ){
    int n,c,e;
    PolyNomial P,Rear;
    P=(PolyNomial)malloc(sizeof(struct PolyNode));
    P->link=NULL;
    Rear=P;
    
    scanf("%d",&n);
    while(n--){
        scanf("%d %d",&c,&e);
        Attach(c,e,&Rear);
    }
    Rear=P;
    P=P->link;//让数组的头结点也存储东西
    free(Rear);
    return P;
}
PolyNomial Add(PolyNomial P1,PolyNomial P2){
    PolyNomial P,Rear,t1,t2;
    P=(PolyNomial)malloc(sizeof(struct PolyNode));
    P->link=NULL;
    Rear=P;
    t1=P1;
    t2=P2;
    while(t1&&t2){
        if(t1->expon==t2->expon){
            if(t1->coef+t2->coef){
                Attach(t1->coef+t2->coef,t1->expon,&Rear);
            }
            t1=t1->link;
            t2=t2->link;
        }else if(t1->expon>t2->expon){
            Attach(t1->coef,t2->expon,&Rear);
            t1=t1->link;
        }else{
            Attach(t2->coef,t2->expon,&Rear);
            t2=t2->link;
        }
    }
    while(t1){
        Attach(t1->coef,t1->expon,&Rear);
        t1=t1->link;
    }
    while(t2){
        Attach(t2->coef,t2->expon,&Rear);
    }
    Rear=P;
    P=P->link;
    free(Rear);
    return P;
}
PolyNomial Mult(PolyNomial P1,PolyNomial P2){
    PolyNomial t1,t2,P,PRear,QRear;
    P=(PolyNomial)malloc(sizeof(struct PolyNode));
    P->link=NULL;
    PRear=P;
    t1=P1;
    t2=P2;
    
    if(!P1||!P2){
        return NULL;
    }
    
    while(t2){
    //先让t1的第一项乘以t2，以P为主式
        Attach(t1->coef*t2->coef,t1->expon+t2->expon,&PRear);
        t2=t2->link;        
    }
    t1=t1->link;
    PRear=P;
    P=P->link;//让P可以进行加法
    free(PRear);
    while(t1){
        PolyNomial Q;//重新定义一个Q，让Q记录每次t1中的一项和t2中相乘后得到的多项式
        t2=P2;
        Q=(PolyNomial)malloc(sizeof(struct PolyNode));
        Q->link=NULL;
        QRear=Q;
        while(t2){
            Attach(t1->coef*t2->coef,t1->expon+t2->expon,&QRear);
            t2=t2->link;        
        }
        QRear=Q;
        Q=Q->link;
        free(QRear);
        P=Add(P,Q);
        t1=t1->link;
    }
    return P;
}
void PrintPoly(PolyNomial P){
    int flag=0;
    if(!P){
        printf("0 0\n");
        return ;
    }
    while(P){
        if(!flag){
            flag=1;
        }else{
            printf(" ");
        }
        printf("%d %d",P->coef,P->expon);
        P=P->link;
    }
    printf("\n");
    
}
int main(){
    PolyNomial P1,P2,PP,PS;
    
    P1=ReadPoly();
    P2=ReadPoly();
    PP=Mult(P1,P2);
    PrintPoly(PP);
    PS=Add(P1,P2);
    PrintPoly(PS);
    
    return 0;
}

input
1 1 1
1 1 1
outout
1 2
2 1
(基本多项式只有1的都可以）
（加法的结果也基本可以）
input
4 3 4 -5 2 6 1 -2 0
3 5 20 -7 4 3 1
然后结果就出不来了