#include<stdio.h>
#include<stdlib.h>
int coe[50],pow[50];
void sort(int start,int end)
{
	int i,j,temp;
	for(i=start;i<end;i++)
	{
		for(j=start;j<end;j++)
		{
			if(pow[i] > pow [j])
			{
				temp=pow[i];
				pow[i]=pow[j];
				pow[j]=temp;
				temp=coe[i];
				coe[i]=coe[j];
				coe[j]=temp;
			}
		}
	}
}
void combine(int start,int end)
{
	int i,j;
	for(i=start;i<end;i++)
	{
		for(j=i+1;j<=end;j++)
		{
			if(pow[i] == pow[j])
			{
				coe[i]+=coe[j];
				pow[j]=0;
				coe[j]=0;
			}
		}
	}
}
void Print(int start,int end)
{
	int i,j=0;
	for(i=start;i<=end;i++)
	{
		if(coe[i] != 0)//係數不為0
		{
			if(pow[i] != 0)
			{
				if(coe[i] == -1 )
				{
					printf("-x^%d",pow[i]);
					j=1;
				}
				else if(coe[i] == 1)
				{
					printf("x^%d",pow[i]);
					j=1;
				}
				else
				{
					printf("%dx^%d",coe[i],pow[i]);
					j=1;
				}

			}
			else
			{
				printf("%d",coe[i]);
				j=0;
			}
		}
		if(j == 1)//係數為0
		{
			if(coe[i] >0)
			{
				printf("+");
			}
		}
		j=1;
	}
}
int main()
{
	int i,j;
	int startA=0,startB,finishA=0,finishB=0,avail;

	while(1)
	{
		printf("請輸入多項式1 (係數 次方):");
		scanf("%d %d",&coe[finishA],&pow[finishA]);

		if(coe[finishA] == 0 && pow[finishA] == 0)
		{
			finishA--;
			startB = finishA+1;
			break;
		}
		else
		{
			finishA++;
		}
	}
	combine(startA,finishA);
	sort(startA,finishA);
	printf("\n多項式1為:\n");
	Print(startA,finishA);

	finishB = startB;
	printf("\n");
	while(1)
	{
		printf("請輸入多項式2 (係數 次方):");
		scanf("%d %d",&coe[finishB],&pow[finishB]);

		if(coe[finishB] == 0 && pow[finishB] == 0)
		{
			finishB--;
			avail = finishB+1;
			break;
		}
		else
		{
			finishB++;
		}
	}
	combine(startB,finishB);
	sort(startB,finishB);
	printf("\n多項式2為:\n");
	Print(startB,finishB);

	for(i=startA;i<=finishA;i++)
	{
		for(j=startB;j<=finishB;j++)
		{
			coe[avail] = coe[i]*coe[j];
			pow[avail] = pow[i]+pow[j];
			avail++;
		}
	}
	combine(finishB+1,avail);
	sort(finishB+1,avail);
	printf("\n");
	printf("相乘過後之多項式為:\n");
	Print(finishB+1,avail);
	return 0;
}