题解 | #[NOIP2010]数字统计#

#include <stdio.h>

int main() {
    int l = 0;
    int r = 0;

    while (2 == scanf("%d %d", &l, &r))
    {
        int count = 0;
        for (int i = l; i <= r; i++)
        {
            int tmp = i;
            while (tmp)
            {
                if (tmp % 10 == 2)
                {
                    count++;
                }
                tmp /= 10;
            }
        }
        printf("%d\n", count);
    }
    
    return 0;
}