algorithm exercise

factorial_summation.cpp

#include <stdio.h>

int main()
{
	auto n = 0;
	const auto modNum = 1000000;
	while (~scanf("%d", &n))
	{
		n = n >= 25 ? 25 : n;

		auto sum = 0;
		for (auto num = 1; num <= n; num++)
		{
			auto factorial = 1;
			for (auto multiplier = 2; multiplier <= num; multiplier++)
			{
				factorial = factorial * multiplier % modNum;
			}
			sum = (sum + factorial) % modNum;
		}
		printf("%d\n", sum);
	}
	return 0;
}