#include <bits/stdc++.h>
using namespace std;
 
bool isPossible(const vector<int>& v, int g, int k) {
    int need = 0;
    for (int x : v) {
        if (x < g) need++;
        else if (x % g == 0) continue;
        else if (x >= 2 * g) continue;
        else need++;
        if (need > k) return false;
    }
    return need <= k;
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int t;
    cin >> t;
    while (t--) {
        int n, k;
        cin >> n >> k;
        vector<int> v(n);
        for (int i = 0; i < n; i++) cin >> v[i];
 
        int lo = 1, hi = *max_element(v.begin(), v.end());
        int ans = 1;
 
        while (lo <= hi) {
            int mid = (lo + hi) / 2;
            if (isPossible(v, mid, k)) {
                ans = mid;
                lo = mid + 1;
            } else {
                hi = mid - 1;
            }
        }
        cout << ans << "\n";
    }
}
 
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6
9 1
4 9 6 8 2 6 7 8 2
10 1
4 9 6 8 2 6 7 8 2 7
7 5
1 1 2 3 4 5 5
7 4
1 1 2 3 4 5 5
14 3
14 12 7 12 9 9 12 4 3 1 3 6 9 13
1 0
1