#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) cin >> a[i];
    int count = a[0];
    for (int i = n - 1; i > 0; i--) {
      a[i] = a[i] - a[i - 1];
      if (a[i] < 0) count = count + a[i];
    }
    if (count >= 0)
      cout << "YES" << endl;
    else
      cout << "NO" << endl;
  }
}
