#include <iostream>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <cstring>
#include <queue>
#include <set>
#include <cmath>
#define ll long long
using namespace std;


int main() {
    int t;
        cin >> t;
        while(t--) {
            int n;
            cin >> n;
            vector<int> v(n);
            for(int i = 0; i < n; i++) {
                cin >> v[i];
            }
            sort(v.begin(), v.end());
            v.resize(unique(v.begin(), v.end()) - v.begin());
            int j  = 0, res = 0;
            for(int i = 0; i < v.size(); i++) {
                while(j < v.size() and v[i] - v[j] >= n) {
                    j++;
                }
                res = max(res, i - j + 1);
            }
            cout << res << endl;
        }
}