单链表实现一元多项式乘法与加法运算（C语言）

#include<stdio.h>
#include <stdlib.h>
typedef struct Node *PtrToNode;
struct Node{
	int coe;
	int exp;
	PtrToNode next;
};
typedef PtrToNode List;
List read();
void Print( List L );
List add(List L1,List L2);
List mul(List L1,List L2);
int main(){
	List L1,L2,LA,LM;
	L1=read();
	L2=read();
	LA=add(L1,L2);
	LM=mul(L1,L2);
	Print(LM);
	Print(LA);
	int a=0;
}

List read(){
	int n;
	List s;
	s=(List)malloc(sizeof(struct Node));
	s->next=NULL;
	scanf("%d",&n);
	if(n){
		List m=s;
		int i;
		for(i=0;i<n;i++){
			List p=(List)malloc(sizeof(struct Node));
			scanf("%d%d",&(p->coe),&(p->exp));
			m->next=p;
			m=p;
		}
		m->next=NULL;
	}
	return s;
}

void Print(List L)
{
	List r=L->next;
	if(r){
		List p=(List)malloc(sizeof(struct Node));
		p=L;
		if(p->next){
			p=p->next;
			//格式需要
			printf("%d %d",p->coe,p->exp);
			while(p->next){
				p=p->next;
				printf(" %d %d",p->coe,p->exp);
		}
		}
	}
	else
		printf("0 0");
	printf("\n");
}
List add(List L1,List L2){
	List pa,pb,pc,L;
    L = (List)malloc(sizeof(struct Node));
	L->next=NULL;
    pa=L1->next;
    pb=L2->next;
    pc = L;
    while(pa && pb)
    {
        if(pa->exp<pb->exp){
			List temp=(List)malloc(sizeof(struct Node));
			temp->next=NULL;
			temp->coe=pb->coe;
			temp->exp=pb->exp;
			pc->next=temp;
			pc=temp;
			pb=pb->next;
		}
		else if(pa->exp==pb->exp){
			int a=pa->coe+pb->coe;
			if(a!=0){
				List temp=(List)malloc(sizeof(struct Node));
				temp->next=NULL;
				temp->exp=pa->exp;
				temp->coe=a;
				pc->next=temp;
				pc=temp;
			}
			pb=pb->next;
			pa=pa->next;
			
			
		}
		else{
			List temp=(List)malloc(sizeof(struct Node));
			temp->next=NULL;
			temp->coe=pa->coe;
			temp->exp=pa->exp;
			pc->next=temp;
			pc=temp;
			pa=pa->next;
		}
	}
	if(pa){
		while(pa){
		List temp=(List)malloc(sizeof(struct Node));
		temp->next=NULL;
		temp->coe=pa->coe;
		temp->exp=pa->exp;
		pc->next=temp;
		pc=temp;
		pa=pa->next;
		}
	}
	else{
		while(pb){
				List temp=(List)malloc(sizeof(struct Node));
				temp->coe=pb->coe;
				temp->exp=pb->exp;
				pc->next=temp;
				pc=temp;
				pb=pb->next;
		}
	}
	pc->next=NULL;
	return L;
}
List mul(List L1,List L2){
	
	List p1,p2,p3,L,Lm;
	L=(List)malloc(sizeof(struct Node));
	p1=L1->next;
	p2=L2->next;
	L->next=NULL;
	if(p1&&p2){
		for(p1=L1->next;p1;p1=p1->next){
			Lm=(List)malloc(sizeof(struct Node));
			Lm->next=NULL;
			p3=Lm;
			for(p2=L2->next;p2;p2=p2->next){
				List p4=(List)malloc(sizeof(struct Node));//尾插法
				p4->coe=p1->coe*p2->coe;
				p4->exp=p1->exp+p2->exp;
				p3->next=p4;
				p3=p4;
			}
			p3->next=NULL;//若不写，则内存出错
			L=add(L,Lm);
			free(Lm);
		}
	}	
	return L;	
}