FAFU OJ 多项式相乘

多项式相乘

Time Limit:	1000MS	Memory Limit:	65536KB
Total Submissions:	311	Accepted:	119

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Description:

      编程实现若干个多项式相乘。多项式的输入输出格式为：系数在前，指数在后，各项按指数递增排列，每个多项式输入时以两个0结束。系数为0的项不输出。例如：1+4X3-9X5输入格式为：1 0 0 1 0 2 4 3 0 4 -9 5 0 0或者 1 0 4 3 -9 5 0 0，其输出只能是： 
1 0 4 3 -9 5

Input:

输入每行为一个多项式，多项式输入时以两个0结束。数据为若干行的多项式，例如： 1 0 1 1 0 0 1 0 -1 1 0 0 1 0 1 2 0 0 表示 （1+x)(1-x)(1+x2) 所有系数、指数均为整数（int类型）

Output:

输出包含1行,为上述多项式相乘结果。上例的输出为： 1 0 -1 4 表示1-x4

Sample Input:

1 0 1 1 0 0

1 0 -1 1 0 0

1 0 1 2 0 0

Sample Output:

1 0 -1 4

Hint:

数据保证不超过十个多项式相乘，单个多项式以上述方式表示的长度不超过一百，指数最大可达到一百万，结果保证在int范围内。

Source:

#include "stdio.h"
typedef struct node
{	int e,c;
	node *next;
}ND;

ND *createLink()
{	ND* head=new ND, *p;
	int c,e;
	p=head;
	while( true )
	{	if( scanf("%d%d", &c, &e)!=2 ) break;
		if( c==0 && e==0 ) break;
		if( c==0 ) continue;
		p->next=new ND;
		p=p->next;
		p->e=e;
		p->c=c;
	}
	p->next=NULL;
	return head;
}

void printLink( ND *head )
{	ND *p=head->next;
	while( p )
	{
		printf("%d %d ", p->c, p->e );
		p=p->next;
	}
	printf("\n");
}

void freeLink( ND *head )
{	ND *p=head;
	while( p )
	{	head=head->next;
		delete p;
		p=head;
	}
}

ND *addLink( ND *ha, ND *hb )
{	ND *hc, *pc, *pa=ha->next, *pb=hb->next;
	int c,e;
	hc=new ND;
	pc=hc;
	while( pa || pb )
	{	if( pa && ( pb==NULL || pa->e<pb->e ) )
		{	c=pa->c;
			e=pa->e;
			pa=pa->next;
		}
		else if( pb && ( pa==NULL || pb->e<pa->e ) )
		{	c=pb->c;
			e=pb->e;
			pb=pb->next;
		}
		else 
		{	c=pa->c+pb->c;
			e=pa->e;
			pa=pa->next;
			pb=pb->next;
		}
		if( c )
		{	pc->next=new ND;
			pc=pc->next;
			pc->c=c;
			pc->e=e;
		}
	}
	pc->next=NULL;
	return hc;
}
ND *multyXmulty( ND *ha, ND *hb )
{	ND *hc=new ND, *pa=ha->next, *ht;
	ND *oneXmulty( ND *pa, ND *hb );
	hc->next=NULL;
	while( pa )
	{	ht=oneXmulty( pa, hb );
		hc=addLink( hc, ht );
		freeLink(ht);
		pa=pa->next;
	}
	return hc;
}
ND *oneXmulty( ND *pa, ND *hb )
{	ND *hc=new ND, *pc=hc, *pb=hb->next; 
	while( pb )
	{	pc->next=new ND;
		pc=pc->next;
		pc->c=pa->c*pb->c;
		pc->e=pa->e+pb->e;
		pb=pb->next;
	}
	pc->next=NULL;
	return hc;
}

int main()
{	ND *ha, *hb, *hc;
//	freopen("1063.in", "r", stdin);


	ha=createLink();
	hb=createLink();
	while( hb->next )
	{	hc=multyXmulty( ha, hb);
		freeLink( ha );
		freeLink( hb );
		ha=hc;
		hb=createLink();
	}
	printLink( hc );
	freeLink( hc );
	freeLink( hb );
	return 0;
}

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