题解 | #[NOIP2010]数字统计#

//BC153[NOIP2010]数字统计  
#include<stdio.h>
int Fun(int L1, int L2)
{
	int n = 0; 
	int count = 0; 
	for (int i = L1; i <= L2; i++)
	{
		n = i; 
		while (n) 
		{
			if (n % 10 == 2)
			{
				count++; 
			}
			n /= 10; 
		}
	}
	return count; 
}
int main()
{
	int L = 0; 
	int R = 0; 
	scanf("%d %d", &L, &R); 
	int ret = Fun(L, R); 
	printf("%d\n", ret); 
	return 0; 
}