func_code_string: #include <bits/stdc++.h>   using namespace std;   void runcase() {     int n, k;     cin >> n >> k;     vector<int> a(n);     for (int i = 0; i < n; i++) cin >> a[i];     int changes = 0;     k--;     for (int i = 1; i < n; i++)       if (a[i] != a[i - 1]) changes++;     int ans = 0;     if (k == 0) {       if (changes == 0)         ans = 1;       else         ans = -1;     } else {       ans = max(1, (changes + k - 1) / k);     }     cout << ans << endl;   }   int main() {     int t;     cin >> t;     while (t--) runcase();     return 0;   }   