prob2.cpp

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

void solve() {
    int t;
    cin >> t;
    
    while (t--) {
        int n;
        cin >> n;
        vector<int> x(n);
        for (int i = 0; i < n; ++i) {
            cin >> x[i];
        }
        
        int min_diff = 100; // Initialize with a large enough value
        for (int i = 1; i < n; ++i) {
            min_diff = min(min_diff, x[i] - x[i - 1]);
        }
        
        if (min_diff > 1) {
            cout << "YES\n";
        } else {
            cout << "NO\n";
        }
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    solve();
    
    return 0;
}