POJ-2897（直接模拟，观察错误情况）（Dramatic Multiplications ）

实在没啥好说的，仅作留念

int main()
{
	int t;
	scanf("%d", &t);
	while (t--) {
		int a, b;
		scanf("%d%d", &a, &b);
		int d[1000];
		d[0] = b;
		int index = 0;
		int flag = 0;
		while (1) {
			int tmp = d[index] * a + flag;
			++index;
			d[index] = tmp % 10;
			flag = tmp / 10;
			if (d[index] == b && flag == 0)
				break;
		}
		if (d[index - 1] == 0) {
			printf("0\n");
			continue;
		}
		for (--index; index >= 0; --index)
			printf("%d", d[index]);
		printf("\n");
	}
	return 0;
}