#include <bits/stdc++.h>
using namespace std;
int a[114514];
int l[114514], r[114514];
bool solve(int n) {
  int curr = a[1];
  l[1] = a[1];
  for (int i = 2; i <= n; i++) {
    if (a[i] < a[i - 1]) curr -= a[i - 1] - a[i];
    if (curr < 0) return false;
    l[i] = curr;
  }
  return true;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    if (solve(n))
      cout << "YES" << endl;
    else
      cout << "NO" << endl;
  }
}
