func_code_string: #include <bits/stdc++.h>   long double pi = acos(-1);   long long z = 1000000007;   long long power(long long a, long long b) {     if (b == 0) return 1;     long long c = power(a, b / 2);     if (b % 2 == 0)       return c * c;     else       return c * c * a;   }   using namespace std;   const int N = 1e6 + 7;   void solve() {     long long n;     cin >> n;     long long k;     cin >> k;     map<long long, long long> m;     for (long long i = 0; i < n; i++) {       long long x;       cin >> x;       m[x]++;     }     if (m.size() <= k)       cout << 1 << endl;     else if (k == 1 && m.size() > 1)       cout << -1 << endl;     else {       long long ans = (m.size() - k) / (k - 1) + 1;       if ((m.size() - k) % (k - 1) != 0) ans++;       cout << ans << endl;     }   }   int main() {     long long t;     cin >> t;     while (t--) solve();   }   