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
"); 
	   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("
");
}