多项式的相乘和相加

参考陈越的数据结构，把其提供的程序重新写了一下，并重新组装。

名称：多项式的相乘和相加

代码如下：

#include <stdio.h>
#include <stdlib.h>
/*
Name: Add and Mult of Polrnomial
Copyright:
Author: demosses
Date: 06/04/17 10:32
Description: 数据结构链表编程题
*/

typedef struct PolyNode *Polynomial;
struct PolyNode{
int coef;
int expon;
Polynomial link;
};
Polynomial ReadPoly();
void Attach(int c,int e,Polynomial *pRear);
Polynomial Add(Polynomial P1,Polynomial P2);
void PrintPoly(Polynomial P);
Polynomial Mult(Polynomial P1,Polynomial P2);
int main()
{
Polynomial P1,P2,PP,PS;

P1=ReadPoly();
P2=ReadPoly();
PP=Mult(P1,P2);
PS=Add(P1,P2);
PrintPoly(PP);
PrintPoly(PS);
}
Polynomial ReadPoly()
{
Polynomial P,Rear,t;
int c,e,N;
scanf("%d",&N);
P=(Polynomial)malloc(sizeof(struct PolyNode));
P->link=NULL;
Rear=P;
while(N--){
scanf("%d %d",&c,&e);
Attach(c,e,&Rear);
}
t=P;P=P->link;free(t); /*删除临时生成的头节点*/
return P;
}
void Attach(int c,int e,Polynomial *pRear)
{
Polynomial P;
P=(Polynomial)malloc(sizeof(struct PolyNode));
P->coef=c;
P->expon=e;
P->link=NULL;
(*pRear)->link=P;
*pRear=P; /*改变尾指针的数值*/
}
Polynomial Add(Polynomial P1,Polynomial P2)
{ /*多项式相加*/
Polynomial t1,t2,P,Rear;
t1=P1;t2=P2;
P=(Polynomial)malloc(sizeof(struct PolyNode));
Rear=P;/*空头节点*/
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,t1->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);
t2=t2->link;
}
t2=P;P=P->link;free(t2);/*删除空的头节点*/

return P;
}
Polynomial Mult(Polynomial P1,Polynomial P2)
{ /*多项式相乘*/
Polynomial P,Rear,t1,t2,t;
int c,e;
if(!P1||!P2)
return NULL;
t1=P1;
t2=P2;
P=(Polynomial)malloc(sizeof(struct PolyNode));
P->link=NULL;
Rear=P;
while(t2){
Attach(t1->coef*t2->coef,t1->expon+t2->expon,&Rear);
t2=t2->link;
}
t1=t1->link;
while(t1){
t2=P2;Rear=P;
while(t2){
e=t1->expon+t2->expon;
c=t1->coef*t2->coef;
while(Rear->link&&Rear->link->expon>e)
Rear=Rear->link;
if(Rear->link&&Rear->link->expon==e)
{
if(Rear->link->coef+c)
Rear->link->coef+=c;
else
{
t=Rear->link;
Rear->link=t->link;
free(t);
}
}
else{
t=(Polynomial)malloc(sizeof(struct PolyNode));
t->coef=c;
t->expon=e;
t->link=Rear->link;
Rear->link=t;
Rear=Rear->link;
}
t2=t2->link;
}
t1=t1->link;
}
t2=P;
P=P->link;
free(t2);
return P;
}
void PrintPoly(Polynomial P)
{ int flag=1;
Polynomial p1=P;
if(!P){
printf("0 0\n");
return; }//马上返回去

while(p1){
if (flag)/*让第一个数输入的不为空格*/
flag=0;
else
printf(" ");
printf("%d %d",p1->coef,p1->expon);
p1=p1->link;
}
printf("\n");
}