题解 | #[NOIP2010]数字统计#

#include <stdio.h>

int num(int l,int r)
{
    int i = 0;
    int count = 0;
    for(i = l;i<=r;i++)
    {
        int m = i;
        while(m)
        {
            if(m%10==2)
            {
                count++;
            }
            m/=10;
        }
    }
    return count;
}

int main()
{
    int L = 0;
    int R = 0;
    scanf("%d %d",&L,&R);
    int ret = num(L,R);
    printf("%d",ret);
    return 0;
}