#include #include #include using namespace std;

int N, C;

bool canPlace(int d, vector& x) { int count = 1; // 第一头牛放在第一个隔间 int lastPos = x[0];

for (int i = 1; i < N; i++) {
    if (x[i] - lastPos >= d) {
        count++;
        lastPos = x[i];
    }
    if (count >= C) return true;
}
return count >= C;

}

int main() { cin >> N >> C; vector x(N); for (int i = 0; i < N; i++) { cin >> x[i]; }

sort(x.begin(), x.end());

int left = 0, right = x[N-1] - x[0];
while (left < right) {
    int mid = left + (right - left + 1) / 2;
    if (canPlace(mid, x)) {
        left = mid;
    } else {
        right = mid - 1;
    }
}

cout << left << endl;

return 0;

}