11625.cpp

#include <bits/stdc++.h>
#define fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)

#define ll long long
using namespace std;

const ll INF = 1e9 + 7;
const ll DIV = 987654321;

int n,w,l;
int arr[10101];
bool ok(int x){
    int cnt = 0, cur = 1;
    for(int i = 0;i < w;){
        int j = i;
        while(j < w && arr[j] - cur + 1 <= x) j++;
        if(i == j){
            cur = arr[j];
        }
        else{
            cur += x;
        }
        i = j;

        cnt++;
    }
    if(cur <= n) cnt++;
    return cnt <= l;
}

int main()
{
    fastio;
    int t;
    cin >> t;
    while(t--){
        cin >> n >> w >> l;
        for(int i = 0;i < w;i++) cin >> arr[i];
        sort(arr, arr+w);
        int s= 1, e = n;
        int ans = INF;
        while(s <= e){
            int m = s + e >> 1;
            if (ok(m))
            {
                ans = m;
                e = m - 1;
            }
            else s = m + 1;
            
        }
        cout << ans << "\n";
    }
    return 0;
}