02-线性结构2 一元多项式的乘法与加法运算 (20 分)

#include 
#include 

typedef struct PolyNode* polynomial;
typedef struct PolyNode{
    int expon;
    int coef;
    polynomial link;
}PolyNode;

polynomial ReadPoly();
void PrintPoly(polynomial P);
void Attach(int c, int e, polynomial *  pRear);
polynomial Mult(polynomial P1, polynomial P2);
polynomial Add(polynomial P1, polynomial P2);

int main(){
	polynomial P1,P2;
	polynomial PP,PS;
	P1=ReadPoly();
	P2=ReadPoly();
	PP=Mult(P1,P2);
	PrintPoly(PP);
	PS=Add(P1,P2);
	PrintPoly(PS);
	/*PrintPoly(P1);
	PrintPoly(P2);*/ 
	return 0;
}

polynomial Add(polynomial p1,polynomial p2){
	int c,e,coeftmp;
	polynomial Rear,temp;
	polynomial t1=p1,t2=p2;
	polynomial P=(polynomial)malloc(sizeof(PolyNode));
	P->link=NULL;
	Rear=P;
	while(t1&&t2){
		if(t1->expon>t2->expon){
			c=t1->coef;
			e=t1->expon;
			Attach(c,e,&Rear);
			t1=t1->link;
		}
		else if (t1->expon < t2->expon)
		{
			//新建结点存储当前t2，插入到链表尾
			c = t2->coef;
			e = t2->expon;
			Attach(c, e,& Rear);
			t2 = t2->link;
		}
		//t1系数等于t2系数
		else
		{
			coeftmp = t1->coef + t2->coef;
			//若系数不为0，则创建结点
			if (coeftmp != 0)
			{
				c = coeftmp;
				e = t2->expon;
				Attach(c, e, &Rear);
			}
			//向下遍历
			t1 = t1->link;
			t2 = t2->link;
		}
	}
	while (t1)
	{
		c = t1->coef;
		e = t1->expon;
		Attach(c, e, &Rear);
		t1 = t1->link;
	}
	while (t2)
	{
		c = t2->coef;
		e = t2->expon;
		Attach(c, e,& Rear);
		t2 = t2->link;
	}
 	return P->link;
}

void Attach(int c,int e,polynomial * pRear){
	polynomial p;
	p=(polynomial)malloc(sizeof(PolyNode));
	p->coef=c;
	p->expon=e;
	p->link=NULL;
	(*pRear)->link=p;
	(*pRear)=p;
}

polynomial ReadPoly()
{
	polynomial P1 = (polynomial)malloc(sizeof(PolyNode));
	polynomial Rear = P1;
	int N, c, e;
	scanf("%d ", &N);
 
	while (N--)
	{
		scanf("%d %d", &c, &e);
		Attach(c, e, &Rear);
	}
	polynomial tmp = P1;
	P1 = P1->link;
	free(tmp);
	return P1;
}
void PrintPoly(polynomial P)
{
	int flag = 0;
	if (!P)
	{
		printf("0 0\n");
		return ;
	}
	while (P)
	{
		if(flag==1)
			printf(" ");
		printf("%d %d", P->coef, P->expon);
		P = P->link;
		flag=1;
	}
	printf("\n");
}
polynomial Mult(polynomial p1,polynomial p2){
	if(!p1||!p2)return NULL;
	int c,e,ctmp,etmp;
	polynomial t1=p1,t2=p2,Rear,Rearbef,tmp;
	polynomial P=(polynomial)malloc(sizeof(PolyNode));
	int flag=0;
	P->link=NULL;
	Rear=P;
	while(t2){//初始化结果链表
		c = t1->coef * t2->coef;
		e = t1->expon + t2->expon;
		Attach(c, e,& Rear);
		t2 = t2->link;
	}
	t1=t1->link;

	while(t1){
		c = t1->coef;
		e = t1->expon;
		t2 = p2;
		while(t2){
			ctmp=c*(t2->coef);
			etmp=e+(t2->expon);
			Rear=P->link;
			Rearbef=P;
			while(Rear)
			{
				 
				if(Rear->expon==etmp){
					ctmp+=(Rear->coef);
					if(ctmp!=0){
						Rear->coef=ctmp;
						t2=t2->link;
						break;
					}
					else{
						tmp=Rear;
						Rearbef->link=Rear->link;
						free(tmp);
						t2=t2->link;
						
						break;
					}
				}
				else if(Rear->expon>etmp){
					Rearbef=Rear;
					Rear=Rear->link;
				}
				 else{
					polynomial x = (polynomial)malloc(sizeof(PolyNode));
					x->coef = ctmp;
					x->expon = etmp;
					x->link = Rear;
					Rearbef->link = x;
					t2 = t2->link;
					break;
				}
			}
			if(Rear==NULL){
				polynomial x = (polynomial)malloc(sizeof(PolyNode));
				x->coef = ctmp;
				x->expon = etmp;
				x->link = NULL;
				Rearbef->link = x;
				t2 = t2->link;
			}
		}
	t1=t1->link;	
	}
	return P->link;
}
/*4 3 4 -5 2  6 1  -2 0
3 5 20  -7 4  3 1*/