#include <bits/stdc++.h>
using namespace std;
int arr[30001];
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
      cin >> arr[i];
    }
    int dp1 = arr[1];
    int dp2 = 0;
    bool fail = 0;
    for (int i = 2; i < n; i++) {
      arr[i] = arr[i] - dp2;
      if (arr[i] < 0) {
        fail = 1;
        break;
      }
      if (arr[i] > dp1) {
        arr[i] = arr[i] - dp1;
        dp2 = dp2 + arr[i];
      } else {
        dp1 = arr[i];
      }
    }
    if (dp2 > arr[n]) {
      fail = 1;
    }
    if (fail) {
      cout << "NO"
           << "\n";
    } else {
      cout << "YES"
           << "\n";
    }
  }
}
