题解 | #[NOIP2010]数字统计#

#include <iostream>

using namespace std;

int main()
{
    int n, m;
    int p = 0, count = 0;
    cin >> n >> m;
    for (int i = n; i <= m; i++)
    {
        int n = i;
        while (n != 0)
        {
            p = n % 10;
            n = n / 10;
            if (p == 2)
            {
                count++;
            }
        }
    }
    cout << count << endl;
    return 0;
}