/*
				poly2.c
				計算機数学 B プログラム 2
				2 変数多項式の和と積
*/
#include <stdio.h>

/*  高々 7 次の多項式の係数を 0 次から辞書式順序で並べる  */
/*static int data1[8][8] =	{{1,1,1,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0}};
static int data2[8][8] =	{{1,0,0,0,0,0,0,0},
							{2,0,0,0,0,0,0,0},
							{3,0,0,1,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0},
							{0,0,0,0,0,0,0,0}};*/
static int data1[8][8] =
	{{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0}};
static int data2[8][8] =
	{{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{1,2,3,4,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0},
	{0,0,0,0,0,0,0,0}};

/*  多項式の構造体を定義する  */
struct polyn2 {
	char var[2]; // 変数の文字
	int deg[2];  // 次数，ただし deg 0 = (-1, -1) とする．
	int coef[8][8]; // coef[i][j] が (i, j) 次の係数
};

/*  関数の宣言  */
void xypoly(struct polyn2 *pf);
void addpoly2(struct polyn2 g, struct polyn2 h, struct polyn2 *pf);
void multpoly2(struct polyn2 g, struct polyn2 h, struct polyn2 *pf);
	 

int main () {
	int i, j;
	struct polyn2 f, g, h;
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			g.coef[i][j] = data1[i][j];
			h.coef[i][j] = data2[i][j];
		}
	}
	xypoly(&g);
	xypoly(&h);
	addpoly2(g,h,&f);
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			printf("%d ",f.coef[i][j]);
		}
		printf("\n");
	}
	printf("\n\n");
	multpoly2(g,h,&f);
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			printf("%d ",f.coef[i][j]);
		}
		printf("\n");
	}
	printf("\n");
	return 0;
}

/*  変数を x とし，次数を調べて記入する  */
void xypoly(struct polyn2 *pf) {
	int i, j, d1=-1, d2=-1;
	pf->var[0] = 'x';
	pf->var[1] = 'y';
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			if (pf->coef[i][j]!=0) {
				if (i > d1) d1 = i;
				if (j > d2) d2 = j;
			}
		}
	}
	pf->deg[0] = d1;
	pf->deg[1] = d2;
	return;
}

/*  多項式 g, h の和を計算し，ポインタ pf を使い結果を f に入れる  */
void addpoly2(struct polyn2 g, struct polyn2 h, struct polyn2 *pf)
{
	int i, j;
	if (g.var[0] != h.var[0] || g.var[1] != h.var[1]) {
		printf("error : polynomial variables are not same");
		return;
	}
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
		pf->coef[i][j] = g.coef[i][j] + h.coef[i][j];
		}
	}
	xypoly(pf);
	return;
}

/*  多項式 g, h の積を計算し，ポインタ pf を使い結果を f に入れる  */
void multpoly2(struct polyn2 g, struct polyn2 h, struct polyn2 *pf)
{
	int i, j, k1, k2, d1, d2, a1, a2, b1, b2;
	if (g.var[0] != h.var[0] || g.var[1] != h.var[1]) {
		printf("error : polynomial variables are not same");
		return;
	}
	if ((d1 = g.deg[0] + h.deg[0]) > 7 || (d2 = g.deg[1] + h.deg[1]) > 7) {
		printf("error : degrees are too large");
		return;
	}
	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			pf->coef[i][j]=0;
		}
	}
	for (k1=0; k1<=d1; k1++) {
		a1 = 0;
		if (k1 > g.deg[0]) a1 = k1 - g.deg[0];
		b1 = k1;
		if (k1 > h.deg[0]) b1 = h.deg[0];
		for (k2=0; k2<=d2; k2++) {
			a2 = 0;
			if (k2 > g.deg[1]) a2 = k2 - g.deg[1];
			b2 = k2;
			if (k2 > h.deg[1]) b2 = h.deg[1];
			for (i=a1; i<=b1; i++) {
				for (j=a2; j<=b2; j++) {
					pf->coef[k1][k2] += g.coef[k1-i][k2-j] *h.coef[i][j];
				}
			}
		}
	}
	pf->deg[0] = d1;
	pf->deg[1] = d2;
	pf->var[0] = 'x';
	pf->var[1] = 'y';
	return;
}