#include <bits/stdc++.h>

#define int long long 

using namespace std;

const int N = 2 * 1e5 + 10;

int n;
int a[N];
int t;

signed main() {
    cin >> t;
    while (t--) {
        cin >> n;
        for (int i = 1;i <= n;++i) {
            cin >> a[i];
        }
        for (int i = 2;i <= n;++i) {
            int t = min(a[i - 1]，a[i]);
            a[i - 1] -= t;
            a[i] -= t;
        }
        bool flg = false;
        for (int i = 2;i <= n;++i) {
            if (a[i] < a[i - 1]) {
                cout << "NO\n";
                flg = true;
            }
            if (flg) break;
        }
        if (flg) continue;
        cout << "Yes\n";
    }
    return 0;
}