4097187_ac_47ms_204k.cpp

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>

__int64 num_0(__int64 n)
{
	if (n < 0)
	{
		return 0;
	}
	if (n < 10)
		return 1;
	__int64 ret = 0;
	__int64 high, low, now, fact = 1;
	while (n / fact)
	{
		low = n - n / fact * fact;
		now = n / fact % 10;
		high = n / (fact * 10);

		if (now == 0)
			ret += (high - 1) * fact + low + 1;
		else
			ret += high * fact;
		fact *= 10;
	}
	return ++ret;
}

int main()
{
	__int64 m, n;
	
	while (scanf("%I64d%I64d", &m, &n) == 2 && m >= 0)
	{
		printf("%I64d\n", num_0(n) - num_0(m - 1));
	}
	return 0;
}