#include<bits/stdc++.h>

using namespace std;

#define lowbit(x) ((x)&(-x))

typedef long long LL;

const int maxm = 1e5+;

const int INF = 0x3f3f3f3f;

int buf[maxm], n;

void run_case() {

    cin >> n;

    int Max = -, Min = INF;

    for(int i = ; i < n; ++i) cin >> buf[i];

    for(int i = ; i < n; ++i) {

        if(buf[i] == -) {

            if(i >  && buf[i-] != -) Min = min(Min, buf[i-]), Max = max(Max, buf[i-]);

            if(i < n- && buf[i+] != -) Min = min(Min, buf[i+]), Max = max(Max, buf[i+]);

        }

    }

    int mid = (Max+Min)>>, ans = ;

    for(int i = ; i < n-; ++i) {

        int a = buf[i], b = buf[i+];

        if(a == -) a = mid;

        if(b == -) b = mid;

        ans = max(ans, abs(a-b));

    }

    cout << ans << " " << mid << "\n";

}

int main() {

    ios::sync_with_stdio(false), cin.tie();

    //cout.setf(ios_base::showpoint);cout.precision(10);

    int t; cin >> t;

    while(t--)

    run_case();

    cout.flush();

    return ;

}