PAT/PATAdvanced/1002.c

#include <stdio.h>
#include <math.h>

typedef struct Poly {
	double coef;
	int exp;
} Poly[20];

int main()
{
	int KA, KB, Ksum = 0;
	Poly A, B, sum;

	scanf("%d", &KA);
	for (int i = 0; i < KA; i++)
		scanf("%d %lf", &A[i].exp, &A[i].coef);

	scanf("%d", &KB);
	for (int i = 0; i < KB; i++)
		scanf("%d %lf", &B[i].exp, &B[i].coef);

	int i = 0, j = 0;
	while (i < KA || j < KB) {
		if (i == KA || (j < KB && A[i].exp < B[j].exp)) {
			sum[Ksum].exp = B[j].exp;
			sum[Ksum].coef = B[j++].coef;
		} else if (j == KB || (i < KA && A[i].exp > B[j].exp)) {
			sum[Ksum].exp = A[i].exp;
			sum[Ksum].coef = A[i++].coef;
		} else {
			sum[Ksum].exp = A[i].exp;
			sum[Ksum].coef = A[i++].coef + B[j++].coef;
		}

		if (fabs(sum[Ksum].coef) >= 0.05)
			Ksum++;
	}

	printf("%d", Ksum);

	for (int i = 0; i < Ksum; i++)
		printf(" %d %.1lf", sum[i].exp, sum[i].coef);

	return 0;
}