D

#include <bits/stdc++.h>

using namespace std;


#define endl "\n"
#define bug(x) cerr << #x << " = " << x << endl
#define sz(x) (int)x.size()
#define mp make_pair
#define LL long long

int n;

void solve(){
    cin >> n;
    vector<int> a(n);
    for(int i = 0; i < n; i ++) cin >> a[i];

    vector<int> vec; vec.clear();
    int L = 0, R = n;
    for(int i = 0; i < n - 1; i ++){
        if(a[i] > a[i + 1]){
            L = max(L, a[i] - a[i + 1]);
            vec.push_back(i);
        }
    }

    if(vec.size() == 0) {
        cout << (1ll + n) * n / 2 << endl;
        return;
    }

    for(int i = 0; i < vec.size() - 1; i ++) if(vec[i] + 1 == vec[i + 1]){
        cout << 0 << endl;
        return;
    }

    for(int i = 0; i < vec.size() - 1; i ++){
        int st = vec[i] + 1, en = vec[i + 1];
        assert(st < en);
        int tmx = 0;
        while(st != en){
            tmx = max(a[st + 1] - a[st], tmx);
            st ++;
        }
        R = min(tmx, R);
    }

    if(R < L) {
        cout << 0 << endl;
    }
    else {
        cout << ((long long)L + R) * (R - L + 1) / 2 << endl;
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    int Tc = 1;
    cin >> Tc;
    while(Tc --){
        solve();
    }

    return 0;
}