1957a95a.cpp

namespace sol
{
    long long a, b;

    const int N = 60;
    long long ten[N], f[N];
    long long cnt_a[N], cnt_b[N];
    long long num[N];

    inline void init()
    {
        ten[0] = 1;

        for (register int i = 1; i <= N - 5; i++)
        {
            f[i] = f[i - 1] * 10 + ten[i - 1];
            ten[i] = 10 * ten[i - 1];
        }
    }

    inline int parse_num(long long x)
    {
        int res = 0;
        memset((num), 0, sizeof((num)));

        while (x)
        {
            num[++res] = x % 10;
            x /= 10;
        }

        return res;
    }

    inline void solve(long long x, long long *cnt)
    {
        int len = parse_num(x);

        for (register int i = len; i > 0; i--)
        {
            for (register int j = 0; j < 10; j++)
            {
                cnt[j] += f[i - 1] * num[i];
            }
            for (register int j = 0; j < num[i]; j++)
            {
                cnt[j] += ten[i - 1];
            }

            long long Num = 0;

            for (register int j = i - 1; j > 0; j--)
            {
                Num = Num * 10 + num[j];
            }
            cnt[num[i]] += Num + 1;
            cnt[0] -= ten[i - 1];
        }
    }

    inline void main()
    {
        init();
        int T;
        io::read(T);

        for (register int _ = 1; _ <= T; _++)
        {
            memset((cnt_a), 0, sizeof((cnt_a)));
            memset((cnt_b), 0, sizeof((cnt_b)));

            io::read(a), io::read(b);

            solve(a - 1, cnt_a);
            solve(b, cnt_b);

            printf("Case %d: %lld\n", _, cnt_b[0] - cnt_a[0]);
        }
    }

} // namespace sol

int main()
{
    sol::main();
}