How many zeros - LightOJ

//Make CSP great again
#include <bits/stdc++.h>
#define TASK "TESTCODE"
using namespace std;
string s;
long long f[10][100][2][2], a, b;
long long dp(int i, int numzeros, bool low, bool zeros)
{
    if (i == s.length())
    {
        return numzeros;
    }
    long long &res = f[i][numzeros][low][zeros];
    if (res != - 1)
    {
        return res;
    }
    res = 0;
    int k = s[i] - '0';
    if (low)
    {
        k = 9;
    }
    for (int j = 0; j <= k; ++ j)
    {
        if (zeros == 0 && j == 0)
        {
            res += dp(i + 1, numzeros, low | j < (s[i] - '0'), zeros | (j != 0));
        }
        else
        {
            res += dp(i + 1, numzeros + (j == 0), low | j < (s[i] - '0'), zeros | (j != 0));
        }
    }
    return res;
}
long long Get(long long x)
{
    s = to_string(x);
    memset(f, -1, sizeof(f));
    return dp(0, 0, 0, 0);
}
void read()
{
    cin >> a >> b;
}
void solve()
{
    if (a == 0)
    {
        cout << Get(b) - Get(a) + 1 << '\n';
    }
    else
    {
        cout << Get(b) - Get(a - 1) << '\n';
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    //freopen(TASK".INP", "r", stdin);
    //freopen(TASK".OUT", "w", stdout);
    int t = 1;
    bool typetest = true;
    if (typetest)
    {
        cin >> t;
    }
    for (int __ = 1; __ <= t; ++ __)
    {
        cout << "Case " << __ << ": ";
        read();
        solve();
    }
}