7-2 一元多项式的乘法与加法运算 (20分)

参考7-2 一元多项式的乘法与加法运算 (20分)
这道题半写半看ppt写出来的，这个链表真的有些难写；
抄完ppt后还是掉了后面两个测试点，然后找个了个老哥的答案对了一下；
问题是乘法的系数相加为零的情况 和 输出p点为NULL情况：

if(rear->next->coef+coef){
					rear->next->coef += coef;
				}
				else{	//系数相加为0，是零多项式
					rear->next->coef=0;
					rear->next->expon=0;
//					temp = rear->next;
//					rear->next = temp->next;
//					free(temp);
}

void PrintPoly(Polynomial p)
{
	int flag = 1;
	if(!p)printf("0 0");
//	下面是省略号
//	。。。。。。

然后代码如下，

#include<bits/stdc++.h>
using namespace std;
typedef struct a *Polynomial; 
struct a{
    int coef;
    int expon;
    Polynomial next;
};
void Attach( int coef, int expon, Polynomial *Prear);//系数， 指数， 尾指针；
Polynomial ReadPoly();
Polynomial Poly_Muti(Polynomial a, Polynomial b);
Polynomial Poly_Add(Polynomial a, Polynomial b);
void PrintPoly(Polynomial tmp);
Polynomial ReadPoly()
{
    int n, coef, expon;
    Polynomial t, p, rear = (Polynomial)malloc(sizeof(struct a));
    p = rear;

    scanf("%d", &n);

    while(n--)
    {
        scanf("%d %d", &coef, &expon);
        Attach(coef, expon, &rear);
    }
    t = p; p = p->next; free(t);
    
    return p;
}
void Attach( int coef, int expon, Polynomial *Prear)    //输入系数， 指数， 尾指针，创建节点，后接，后移
{
    Polynomial p;

    p = (Polynomial)malloc(sizeof(struct a));   //新建节点；
    p->coef = coef;         //赋值；
    p->expon = expon;
    p->next = NULL;
    (*Prear)->next = p;     //节点接到尾指针后；
    *Prear = p;             //尾指针后移，指向后接节点；
}
Polynomial Poly_Muti(Polynomial a, Polynomial b)
{
	int coef, expon;
    Polynomial temp,   t1 = a, t2 = b, rear, p = (Polynomial)malloc(sizeof(struct a));
    p->next = NULL;
    rear = p;
    if(!a||!b) return NULL;
    
    while(t2)
    {
    	if(t1->coef*t2->coef) 
        Attach(t1->coef*t2->coef, t1->expon+t2->expon, &rear);
        t2 = t2->next;
    }
    t1 =t1->next;
    while(t1)
    {
    	t2 = b; rear =p;
    	while(t2)
    	{
    		coef = (t1->coef) * (t2->coef);
    		expon = t1->expon + t2->expon;
    		while(rear->next && rear->next->expon > expon)
				rear = rear->next;
			if(rear->next&&rear->next->expon==expon)
			{
				if(rear->next->coef+coef){
					rear->next->coef += coef;
				}
				else{	//系数相加为0，是零多项式
					rear->next->coef=0;
					rear->next->expon=0;
//					temp = rear->next;
//					rear->next = temp->next;
//					free(temp);
				}
			}
			else
			{
				temp =(Polynomial)malloc(sizeof(struct a));
				temp->coef = coef;temp->expon = expon;
				temp->next = rear->next;
				rear->next = temp;rear = rear->next;
			}
    		t2 = t2->next;
		}
		t1= t1->next;
	}
	t2 = p; p= p->next;free(t2);
	return p;
}
Polynomial Poly_Add(Polynomial a, Polynomial b)
{
    Polynomial t, phead, t1, t2, rear;
    t1=a,t2=b;
    phead = (Polynomial)malloc(sizeof(struct a)); phead->next = NULL;
    rear = phead;
    while(t1&&t2)
    {
        if(t1->expon > t2->expon)
        {
            Attach(t1->coef, t1->expon, &rear);
            t1 = t1->next;
        }
        else if(t2->expon > t1->expon)
        {
            Attach(t2->coef, t2->expon, &rear);
            t2 = t2->next;
        }
        else{
        	int coefSum=t1->coef+t2->coef;
        	if(coefSum!=0){
				Attach(coefSum, t1->expon, &rear);
			}
			t1=t1->next;
        	t2=t2->next;
		} 
    }
    while(t1)
    {
        Attach(t1->coef, t1->expon, &rear);
        t1 = t1->next;
    }
    while(t2)
    {
        Attach(t2->coef, t2->expon, &rear);
        t2 = t2->next;
    }
    t = phead;
    phead = phead->next;
    free(t); //去头节点；
    return phead;
}
void PrintPoly(Polynomial p)
{
	int flag = 1;
	if(!p)printf("0 0");
	while(p)
	{
		if(flag)
			flag = 0;
		else printf(" ");
		printf("%d %d",p->coef,p->expon);
		p=p->next;
	}
	printf("\n");
}
int main(void)
{
    Polynomial a, b, mc, ac, p, pp;
    
    a = ReadPoly();
    b = ReadPoly();
    mc = Poly_Muti(a, b);
    PrintPoly(mc);
    ac = Poly_Add(a, b);
    PrintPoly(ac);
}

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标签：20,coef,多项式,t2,next,加法,Polynomial,expon,rear
来源： https://blog.csdn.net/dylan_sjc/article/details/104202620